EOSC 118 Module A
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Created by:
courtneydv on July 30, 2012
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585 terms
Terms | Definitions |
|---|---|
 Where is the Koh-I-Noor diamond found? | Sits within the Queen Mother's Crown |
| Carat of the its within Koh-I-Noor diamond? | The current weight of the stone is 105.6 carats, significantly less than the original ~186 carats. (Recut in 1852) |
| What is the largest rough diamond ever found? | The Cullinan Diamond |
| Original weight of the The Cullinan Diamond? | 3106 carats |
| What did the Cullinan diamond yield? | Nine significant stones, 96 smaller stones and some extra 'bits and pieces |
| Nine significant diamond names? | Cullinan I through IX and reside with the British Royal Family and Crown Jewels. |
| Cullinan 1 carat / name / location? | 530.2 carats, the Star of Africa, is mounted in the Royal Scepter |
| Cullinan 2 carat/ location? | 317.40 carats, is mounted in the Imperial State Crown |
| Cullinan 3/4 carat/location? | 94 and 64 carats respectively, are set together in a single brooch. |
| Hope Diamond characteristics? | deep blue colouration and lack of internal flaws |
| Hope diamond carats? | 45.52 carats |
| Hope diamond clarity? | VS1 |
| Hope diamond cut? | Cushion Antique Brilliant |
| Hope diamond first mined from... | India from the Golconda region |
| Wittlesbach Diamond carat? | 35.56 carats and is the current record holder for the most expensive diamond ever sold at auction |
| Wittlesbach sold for how much? | $24.3 million USD, which translates to ~$680,000 per carat |
| What diamond is sold for highest price per carat? | 0.95 carat Hancock Red Diamond that sold for ~$925,000 USD per carat. |
| Cullinan I estimated minimum value? | $360 million USD. |
| What is the largest polished diamond? | Golden Jubilee, 755.5 carats rough, 545.67 carats cut, origin: Premier mine SA |
| Where are most of the largest polished diamonds from? | South Africa (Premier mine) |
| First known use of emeralds as decorative stones? | By the Pharaohs of Egypt |
| What makes an old world emerald? | The stones from the Egyptian deposits, they did not have the quality that is seen from the deposits mined today |
| Mogul Emerald? | Mined in India's Rajasthan State and are often classified as Mogul Emeralds because their extraction was commissioned during the reign of the Mughal Empire (Similar quality of Egypt's) |
| Where do New World emeralds come from? | Mines of Colombia |
| What is distinct about the emeralds that are mined from Columbia? | Consistently more vivid, cleaner, and often larger than emeralds from anywhere else in the world |
| Mogul Emerald (mined from where, shipped to where, carat / description) | Columbia to India 217 carat rectangular shape Inscribed with Islamic text w/ poppy flowers |
| How much was the Mogul emerald auctioned for? | $2.2 million USD |
| Hooker Emerald (carat, where is it now?) | 75 carats Set in a Tiffany-designed platinum brooch @ Smithsonian Institute's Museum of Natural History |
| History of owners of the Hooker Emerald? | 1. Salomon Habib 2.Sultan Abdul Hamid II 3. Janet Hooker |
| What is one of the largest uncut Colombian emeralds? | Patricia Emerald |
| Patricia Emerald carat? | 632 or 126 grams |
| Patricia Emerald location? | American Museum of Natural History's collection of precious minerals and gems since 1921. |
| Where do rubies of the finest quality originate from? | Burma, or what is known today mostly as Myanmar. |
| What is the colour of the finest ruby stones referred to as? | Pigeon's Blood Red - a red to purple-red colour with medium-dark tone that is enhanced by a red fluorescence |
| What is one of the finest cut rubies? | Mogok Ruby, also known as the Alan Caplan Ruby |
| Mogok ruby carat? | 15.97 carats |
| How much was the Mogok ruby sold for? | $3,630,000 - resulting in a per carat value of $227,301 |
| Who was the Mogok ruby sold to and for what purpose? | Sultan of Brunei who apparently used it as an engagement ring |
| Burmese ruby sold for? | Was 8.62 carats and fetching $US 3,621,000 - resulting in a per carat value of over $400,00 per carat. |
| Name the two famous start rubies? | Burmese DeLong Star Ruby Rosser Reeves Ruby |
| Burmese DeLong Star Ruby carat / history? | 100.32 carats and is on display at the American Museum of Natural History. Stolen in 1964, it was returned for a reported $25,000 USD ransom by thief, Jack Murphy |
| Rosser Reeves Ruby carat/ history? | Smithsonian National Museum of Natural History and weights 138.7 carats. |
| What is the most famous ruby? | Black Prince's Ruby |
| What stone is the Black Prince's Ruby actually? | A red spinel |
| Location of the Black Prince's Ruby? | Set in the Imperial State Crown just above the Cullinan II diamond |
| Black prince's ruby history? | Starts in 1366 AD in Spain following which was is a lengthy story filled with trials and tribulations |
| Koh-I-Noor history? | Prominently in south Asian history 1849: Ending up as part of the Enghsh Crown Jewels after the British conquest of the Punjab. |
| Original form of the Koh-I-Noor diamond? | - 169 facets, had a higli-domed crown, flat base, and predominantly triangular and rectangular facets covering its surface, |
| Where do they think the Koh-I-Noor diamond came from? | India's Golconda region |
| Koh-I-Noor diamond aka? | Mountain of Light |
| Cut of the modern Koh-I-Noor diamond? | Oval cut |
| Color of the Koh-I-Noor diamond? | D-color type IIa stone |
| Other info about Koh-I-Noor diamond? | Is inert to long-wave UV ratiiation but shows a weak green reaction to short-wave UV. Although it lias not been given a clarity grade, it shows several feathers/gletzes and a black inclusion under its table |
| What country has historically produced the most gold? | South Africa (11%) |
| What Country has surpassed South Africa in gold production this year? | China (12%) |
| Other countries producing significant quantities? | Australia, North and South America |
| Where is Canada ranked in gold production? | 8th largest producer (4%) |
| Where does most of the gold originate from in Canada? | Hard rock mines in Ontario, Quebec, and British Columbia. |
| What is the total amount of gold produced on a yearly basis? | ~2,500 tonnes |
| What is the most consumption for gold? | Jewellery production (83% of global consumption) |
| What is the remainder consumptions for gold? | Primarily by electronics, currencies and investments. |
| Barrick Gold of Canada | The largest non-Chinese producer of gold. It is responsible for approximately 10% of the market share, generated from 27 active mines on 4 continents. |
| AngloGold Ashanti of SA | 20 mines in 10 countries on 4 continents, produce 7% of world's new gold |
| Newmond Mining of US | mines in 9 countries on 5 continents, produce 7% world's new gold |
| How is new gold distinguished from total gold? | In global production number because a significant amount of gold is recycled or pulled from central stockpiles when demand is high. |
| What does PGM stand for? | Platinum group metals (also platinum group minerals) |
| What is platinum (Pt) commonly found with? | palladium (Pd), rhodium (Rh), ruthenium (Ru), iridium (Ir) and osmium (Os) |
| What is rarer gold or PGM's? | PGM's |
| Diff b/w PGM's and gold? | Have a number of high-tech applications and less are produced annually - Higher melting point, exhibit very good durability and strength |
| In general what is the most expensive PGM? | Rh |
| In general what is the least expensive PGM? | Pd |
| What sits b/w the least/most expensive PGMs? | Pt |
| Use in jewellery accounts for what in PGMs? | 30% of the global consumption of platinum and palladium |
| Where does the rest go? | Primarily to autocatalysts (with 15% into electronics) |
| What mainly dictates the price of PGMs? | By the global supply balanced by the demand in the autocatalyst and jewellery markets. |
| What is the global supply of PGMs? | 475 tonnes (or ~17 million ounces) |
| Where do PGMs mainly come from? | South African Bushveld Region Minor contributions come from Palabora and the Witwatersrand Basin |
| What are the two main producers of PGM? | South Africa (79%) and Russia (12%), with significant tonnages provided by the US (2%) and Canada (4%) |
| Where does Canada's production of PGMs come from? | Lac des Iles operation near Thunder Bay - As a secondary product from the Sudbury Complex's nickel deposit in Sudbury, Ontari |
| Where does the US's production of PGMs come from? | Stillwater Complex |
| What is the largest producer of platinum? | Anglo Platinum Group Ltd. - with several operations in South Africa and Canada. |
| What company has essentially controlled the entire diamond market? | De Beers Consolidated Mines Ltd since 1888 |
| Who has maintained / kept prices high for this tightly moderated commodity | - Diamond Trading Company (DTC) -global network of Sightholders - Diamond Bourses - De Beers |
| Steps involved in bringing a diamond to the market? | 1. Geological prospecting and exploration 2. Mine development and mining 3. Sorting, valuing, and sighting of rough stones (DTC) 4. Cutting and polishing into finished diamonds 5. Jewellery manufacturing and distribution 6.Retail stores and sales 7.End consumer |
| 1. Geological prospecting and exploration | Diamonds are found |
| 2. Mine development and mining | Then pulled from the ground, sorted into gem, near-gem and non-gem parcels. |
| 3. Sorting, valuing, and sighting of rough stones (DTC) | The Diamond Trading Company coordinates delivery of raw goods from the mine to optimized parcels for Sightholders - Within these parcels are also divisions based on size, colour, and clarity of the rough diamonds. |
| What are the packages called in step 3? | Sights |
| 4. Cutting and polishing into finished diamonds | Rough diamonds are then faceted and transformed into what we as consumers usually encounter - polished gemstones |
| What are the historical cutting houses? | In Antwerp, Mumbai, New York and Johannesburg |
| Where are the lower cost cutting facilities located? | India, Thailand, and China. |
| When did DeBeers control of the global diamond trade begin to diminish? | With the establishment of Australia's Argyle Mine in the 1980's |
| What was Canada's first diamond mine? | Late 1990's Ekati (operated by BHP Billiton) |
| Other Canadian diamond mines? | 2. Rio Tinto opened Diavik, 3. Tahera Diamond Corp's Jericho Project in 2006. By the end of 2007 these three diamond mines in Canada were already providing 12% of the global production of diamonds with a value of ~Can$1.7 billion. |
| What aids the tight control of diamonds on a global scale? | The Kimberely Process |
| Why is the diamond market more competitive now? | Because of the huge amount of money invested in creating this industry |
| What % of mined diamonds end up being turned into polished goods? | 20% |
| What is the remaining 80% of diamonds used for? | Industrial applications |
| What are the non gem diamonds called? | Bort |
| What is the common use for the non gem diamonds? | Axploited for their phenomenal physical properties --> as abrasives. |
| What is the most reputable / stringent diamond grader? | GIA |
| What does GIA stand for? | Gemological Institute of America |
| Name some other labs? | International Gemological Institute (IGI), American Gem Society (AGS), and European Gemological Laboratories (EGL) |
| What will the reports by these organizations include? | Cut, quality, colour, clarity and carat weight - Physical dimensions and enhancements - Info of stone's origin |
| What are the organizations formed by retailers and manufacturers? | American Gem Trade Association (AGTA), Canadian Gemological Association (CGA), Canadian Jewellers Association (CJA), and Jewelers Circular Keystone (JCK) |
| What carat does a gem have to be to not go to a consumer? | Over 50 carats |
| What carat will mid-range and high-end jewellery stores will often carry? | Stones up to 15 carats |
| Name the two most renowned auction houses? | Christies and Sotheby's |
| Name Luxury brands? | - Tiffany & Co - Harry Winston Inc - Van Cleef and Arpels |
| Tiffany and Co | New York in 1837 and is well associated with "The Tiffany Diamond", a 128.54 carat fancy yellow diamond. |
| Harry Winston | - Started a very successful jewellery company in the US. -Dealt with creating jewellery and was involved in the buying and selling of famous pieces (such as the Spanish Inquisition Necklace) -Donated many stones to the Smithsonian Institution (e.g., the Hope Diamond and the Oppenheimer Diamond) - Helped create one of the most fantastic publicly owned gemstone collections in the world |
| Van Cleef & Arpels | Founded in 1896 in Paris, France, and served much of the European elite. Ex) Princie Pink Diamond Pendant and the Empress' Crown of the Iranian Crown Jewels. |
| What does "the code" stem from? The Voluntary Code of Conduct for Authenticating Canadian Diamond | Competition Bureau's Enforcement Policy on the Marketing of Canadian Diamonds |
| What does the code state? | That a diamond which was mined in Canada qualifies for the purposes of the Competition Act and may be cut and polished in Canada or abroad. |
| What does the code establish? | A minimum standard required to authenticate a Canadian diamond claim based on records and a chain of warranties |
| Who administers the code? | The Canadian Diamond Code Committee (CDCC) |
| What properties of gold have allowed it to form jewellery / religious items? | Its resistance to corrosion, beautiful colour and malleable nature. |
| What has changed to define a gems current value? | Modern exploration and mining practices coupled with increased diversification of global wealth has generated a significant market accessible to individuals other than royalty and the ultra-wealthy. |
| What accompanied the modern practices? | By clever marketing, especially in North America, that has driven the demand level dramatically since the early 1900's |
| What are prices of diamond like now? | The increase in demand has increased production, and therefore brought prices down considerably based on economies of scale |
| When was the gold standard abandoned? | 1971 |
| How does the value of precious metals fluctuate? | With global economic conditions |
| Gold value today? | Has reached local peaks over 1000 USD per ounce in March 2008 and February 2009, and continues to be very highly valued today. |
| AuDITION | Sponsored by the World Gold Council and Anglogold Ashanti. - competition focuses on innovative jewellery designs specifically in high-karat gold. |
| American Gem Trade Association (AGTA) | Hosts a well-known design competition in North America. - aimed primarily at the US custom-jewellery market and awards are given for a number of different categories |
| What did the Kimberly process do? | An industry-driven set of regulations, was voluntarily adopted by the majority of the diamond producing and consuming countries of the world in a fight to quench the trade of illicit diamonds |
| What are some initiatives working towards responsible practices? | The Initiative for Responsible Mining Assurance (IRMA) and the Responsible Jewellery Council (RJC) |
| What are green products? | In the precious metals and gems world have largely been dominated by recycled materials, either from remelting of old pieces or simply reusing antiques. |
| Name the corporate leaders who are certifying their products? | Maple leaf diamonds / CanadaMark - are certified as products of the Ekati and Diavik diamonds mines of the Northwest Territories |
| What does "Certified Canadian Gold" mean? | Ensures that all products with this stamp use only gold that has been mined and refined in Canada |
| Blue Nile | Is an example of a company that is selling diamonds and jewellery online in an honest and secure manner |
| Define Earth Science System. | Views the Earth as a working system, each part having an impact and an effect on the other |
| Where do diamonds form within the earth? | Deep within the Earth in the region called the Upper Mantle |
| Why is the upper mantle ideal to form minerals? | It is where the great pressures and temperatures allow the mineral to grow. |
| What can move diamonds up to the surface where they can be mined? | Glaciation + other natural processes. |
| What do these natural processes do to these diamonds? | Can move the diamonds away from their original source and leave a "cookie crumb trail" to where the real treasure lays (the 'primary deposit') |
| Secondary Deposit? | Diamonds were moved from a 'primary source' by another process and deposited in the same location, by a river for example, then a new diamond deposit can form far away (a 'secondary deposit') from the original source. |
| List the layers of the earth from outer to inner? | 1. Crust - Lithosphere 2. Upper mantle - Asthenosphere 3. Lower mantle 4. Core -Outer fluid core -Inner solid core |
| Name the steps of the scientific investigation | 1. Compile observations 2. Form a hypothesis 3. Test the hypothesis 4. Repeated testing 5. Theory into law 6. Continual re-examination |
| 1. Compile observations | Making detailed unambiguous and clear observations is vital to any scientific investigation |
| 2. Form a hypothesis | This is a provisional theory to explain the observations made. |
| 3. Test the hypothesis | Testing the hypothesis made. |
| 4. Repeated testing | Raises the hypothesis to the level of a Theory. |
| What is a theory? | As such a theory is not a 'guess' but something that has been tested in many different ways and found to be true after each testing. |
| 5. Theory into law | If a theory or group of theories are always observed to happen it could be raised to the level of a Law. |
| 6.Continual re-examination | Tested and reinterpreted |
| What layers are in the lithosphere? | Consists of continental and oceanic crust and the uppermost part of the mantle |
| What does this layer look like? | Is fractured into a number of rigid sections or plates |
| What is the composition of the continental crust? | Much richer in minerals containing silicon (Si) |
| What is the composition of the ocean crust? | Has a higher iron (Fe) content |
| Diff b/w continental and oceanic crust? | Continental tends to be much thicker than oceanic crust. |
| Describe the Asthenosphere. | The upper mantle material acts as a relatively soft, lubricating layer over which the crustal lithospheric plates move. |
| Composition of the Mantle? | A relatively hot viscous "taffy-like" layer |
| What happens in the mantle? | Is in continual motion with hot mantle material rising from the depth and cooler upper mantle material sinking to the lower areas. |
| What are the motions in the mantle called? | Convection currents |
| What do convection currents help drive? | The motion of the lithospheric plates |
| Composition of the outer core? | Liquid |
| Composition of the inner core? | Solid and has a metallic composition. |
| How deep is the earth's interior? | 6,370 km |
| What is the Theory of Plate Tectonics often called? | The geological Grand Unifying Theory |
| What does the theory of plate tectonics describe? | Describes how the plates and the continents they contain are pushed and pulled around the surface of the Earth |
| Where does the most geological activity occur? | Earthquakes, volcanic activity, and mountain building that affects the surface of the Earth occurs at the plate boundaries |
| What parts remain stable? | Central portions of the plates |
| Name the three main types of plate boundaries? | 1. convergent 2. divergent 3. transform |
| What are divergent plate boundaries called? | Constructive |
| What happens at divergent plate boundaries? | Tectonic plates move away from each other at these boundaries and new crust is produced. |
| What /where can divergent plate boundaries form? | Can form within a continental plate to ultimately form a new ocean basin |
| Name an example of a constructive plate boundary. | Mid-Atlantic Ridge (MAR) (can be observed on land in Iceland) |
| What is the section of the MAR that you can see on land called? | Reykjanes Ridge. |
| What happens at convergent boundaries? | Two plates move toward each other and collide |
| Example of a convergent boundaries? | The Himalaya mountain range was formed when two continental plates, the Indian and Eurasian plates, collided (continental-continental collision). |
| What does it mean by subducted? | When two oceanic plates or an oceanic plate and a continental plate are in collision, one plate is pushed under or subducted below the other |
| How are a chain of volcanic islands developed? | When two oceanic plates collide, they develop above the zone of subduction. |
| What plate is subducted in the case of oceanic-continental plate collision? | The oceanic plate is always subducted below the continental plate because oceanic crust is denser than continental material |
| What develops in the case of oceanic-continental plate collision? | Mountain ranges that run along the edge of a continent. Ex) The Cascades in North America |
| What are gems? | Are valuable minerals that originated from an original rock. |
| What is a gemstone? | Is any mineral that is highly valued for its beauty, durability, and rarity. |
| What else is included in gemstone definition? | Are non-mineral gemstones that are organic or biological in origin, such as pearls and amber. |
| What is the diff. b/w a rock and a mineral? | Rocks can essentially be thought of as aggregates of minerals |
| Lengthy definition of a mineral | A mineral is a naturally occurring homogeneous solid with a definite (but generally not fixed) chemical composition and a crystalline structure. It is usually formed by inorganic processes |
| What are the basic three-fold classification of rocks? | - Igneous - Metamorphic - Sedimentary |
| How are these rocks related to one another? | Via processes that change from one type to another over time |
| How do extrusive igneous rocks form? | From magma that cools as it reaches the surface of the Earth |
| How do intrusive plutonic igneous rocks form? | Intrude from below the subsurface, cool, crystallize, and eventually are exposed by erosion at Earth's surface |
| How do metamorphic rocks form? | As a result of the transformation of existing rock |
| How do sedimentary rocks form? | From sediments such as chalk, limestone, dolomite, sandstone, conglomerate, and shale that are then compacted and converted to rock by the process of lithification. |
| Igneous Rocks | - crystallize from a molten material to form a rock composed of interlocking crystals |
| What is the crystallization of igneous rocks called? | Solidification |
| What is the molten material called? | A melt or magma |
| How is melt generated? | From a process called "partial melting" of mantle material or of rocks deep in the crust |
| If this melt cools to form a rock at the surface of the Earth what is it called? | Valcanic or extrusive igneous rocks |
| If the melt cools and solidifies inside the Earth what is it called? | Plutonic or intrusive igneous rocks |
| Metamorphic rocks formed by what process | Metamorphism |
| What is metamorphism? | The alteration of pre-existing rocks (igneous, metamorphic, and sedimentary) |
| What do the process of metamorphising rocks involve? | -Heat - Pressure - Fluids percolating through the subsurface |
| How can new minerals develop in metamorphic rocks? | Rocks can be compressed and flattened and new minerals may be generated that are more stable under the new temperature and/or pressure conditions. |
| What is pressure often a result of? | Compressional tectonic forces generated when plates collide; this can also generate heat. |
| What increase with depth? | Pressure and temperature. |
| Name the processes in which sedimentary rocks can be formed. | 1. Physical erosion / weather of another rock 2. Chemical precipitation to form evaporite 3. Biological precipitation of minerals |
| What does physical erosion / weather of another rock form? | A classic sedimentary rock such as a sandstone, siltstone, or mudstone. |
| What are classic sedimentary rocks composed of? | The fragments and grains of the rock(s) that were being eroded to form the sediment. |
| When does evaporite form? | When a body of water such as a lake or inland sea evaporates to form layers of salt. |
| What does biological precipitation of minerals produce? | The production of coral reefs, sediments composed of shells, and deposition of plant material in swamps to form coal |
| How are sediments transformed into rock? | Via a process called diagenesis or lithification |
| What happens during diagenesis / lithification? | Physically cements the sedimentary grains together |
| What does diagenesis involve? | Heat, pressure, and prelocating fluids but less than metamorphism b/c the rocks are not transformed |
| What is the rock cycle? | Describes how rocks can be transformed by various Earth processes into any other rock in the three-fold classification |
| Partial melting of mantle material forms... | Magma |
| Magma crystallizes to forms... | Igneous rocks |
| Weathering and erosion of igneous and metamorphic rock produces... | Sediments |
| Sediments lithify to form... | Sedimentary rocks |
| Some igneous and sedimentary rock undergo tectonic burial and metamorphism to form... | Metamorphic rock |
| What are all particles made up of? | Atoms |
| What are atoms made up of? | Protons, electrons, neutrons. |
| What are elements? | Matter composed of identical atoms |
| What is the identity of an atom determined by? | The number of protons it contains. |
| Golds (Au) atomic number? | 79 |
| Protons carries what kind of charge? | A single positive charge. |
| Neutrons | - Roughly the same # as protons - Carry no electrical charge |
| Define atomic mass. | The total number of neutrons and protons. |
| What is the weight of atoms given in? | Atomic mass units (amu) Protons = 1 Neutrons = 1 |
| Atomic mass of gold? | 196.967 |
| As atomic mass increases so does what? | The density of the material. |
| Copper: atomic number/mass/denisty | - 29 - 63.546 - 8.9 |
| Silver: atomic number / mass/ density | - 47 - 107.868 - 10.5 |
| Gold: atomic number / mass/ density | - 79 - 196.967 - 19.3 |
| Where are protons / neutrons located? | In the nucleus or core of the atom. |
| Where are the electrons located? | Orbit the atomic core in an unpredictable but organized electron cloud |
| Ionic/atomic charge | The sum of the protons / electrons. |
| What are charged ions called? | Ions |
| What is the valence state of the atom? | When atoms lose / gain electrons and the resulting charge is called the valence state. |
| Cations | Positively charged ions |
| Anions | Negatively charged ions |
| Where does the exchange of electrons occur? | The outermost portion of the electron cloud |
| What is a compound? | Two or more elements. |
| How to elements combine? | Through chemical bonds. |
| What are most gemstones? | Compounds |
| Sapphire | (Al2O3) composed of aluminum (Al) and O |
| Emeralds | (Be3Al2Si6O18) composed of beryllium (Be), Al, silicon (Si), and O |
| How are mixtures differ from compounds? | A mixture is comprised of two or more compounds that are not interacting through chemical bonding |
| Example of a mixture? | A rock --> bulk of mixtures held together through an interlocking physical network of mineral grains not through chemical bonding |
| Name the two main types of bonding. | Ionic and Covalent |
| Ionic bonding | Occurs between two atoms, one with a strong tendency to gain electrons (the anion) and the other with a strong tendency to lose electrons (the cation) |
| What is the most common bonding that happens in the mineral world? | Ionic |
| Covalent bonding | Occurs when atoms "share" valence (or outermost) electrons between them. |
| What compound is covalent bonding more common in? | Organic compounds |
| What gem is covalent bonding prominent in? | Diamond |
| What are diamonds made up of? | Carbon - The carbon atoms share electrons between them -These covalent bonds are very strong and give diamond its hardness and strength. |
| Metallic bonding | Is typical in metals such as silver, gold, and copper. Valence electrons in metallically bonded compounds are shared throughout the entire material and are free to move about = electricity. |
| Name the three states of matter. | Solid, liquid and gas. |
| What is the melting point of gold? | ~1065 °C |
| What temp can gold be turned into a gas? | If heated past its boiling point of ~2856 °C. |
| How are the periodic table of elements arranged? | In order according to atomic number, or elemental identity. |
| Rows of periodic table | Called periods (7 of them) |
| Columns | Groups (18) |
| Subset of two periods | Actinides and Lanthanides |
| What will the period table give you? | List the given name, the atomic number=number of protons, the atomic symbol , and the average atomic mass |
| Why do elements within a group have similar chemical behaviour? | Because of the similarity in the distribution of their electrons, especially in the valence (outermost) shell |
| Alkali metals | Tend to give up an electron, resulting in a characteristic +1 valence charge - 1st group (Na) |
| Alkaline earth metals | These elements usually lose two electrons, resulting in a characteristic +2 valence charge. - 2nd group (Ca/Mg) |
| Transition metals | Middle block of elements - can have variable valence charges, usually up to +4 but sometimes as high as +6 - |
| What metals are transition metals? | Precious metals Cu (copper), Ag (silver), and Au (gold) are all Group 11 transition metals |
| Group 10 elements | The metals Pt (platinum), Pd (palladium), and Ni (nickel) |
| Semi metals or other metals | These include aluminum (Al) and lead (Pb) |
| Metalloids | Including silicon (Si) and arsenic (As) |
| Nonmetals | Include the biologically important elements carbon (C), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S) |
| Halogens | - will almost always have a -1 charge. - chlorine (Cl) and iodine (I). |
| Noble gases | Do not combine with other elements. - helium (He) and neon (Ne). |
| Elements from transition metals produce what? | Often endow gemstones with their striking colours |
| Name the elements that make up the earth's crust | Oxygen, Silicon, Aluminum, Iron, Calcium, sodium, potassium, magnesium and then all others |
| What element is most predominant in the earth's crust? | Oxygen (46%) |
| Are precious metals in the earth's crust common? | No, very rare. |
| Rare earth elements aka | Lanthanide Series |
| Concentration of Au in earths crust? | 10-3, or 0.001 part for every million. |
| What is a native state of an element? | When elements occur by themselves in rock (i.e., not chemically bonded to other elements). |
| How many elements occur in their natural state? | 20 elements - are either metals, semi metals or non metals and considered to be minerals |
| Examples of native state elements | Au, Ag, Cu, and Pt |
| Example of a non-metallic mineral. | Diamond (pure C) |
| Example of a semi-metal mineral | Arsenic (As) |
| Metal oxide | Most metals, when exposed to oxygen in the air will react or corrode to form this. |
| Base metals | - react w/ oxygen to form metal oxide - Fe / Cu |
| What are base metals normally found in nature as? | - Oxide minerals (chemically bonded to oxygen) - Sulfide minerals (chemically bonded to sulfur) |
| Noble metals | Metals that do not react to oxygen |
| Examples of noble metals | Au and Pt |
| Precious metal | Is indicative of the value of a metal, but does not have any chemical connotations ex) Uranium |
| Four primary native metals | Gold, silver, copper, and platinum |
| What bond do the native metals have? | Metallic bonds |
| Common traits of native metal minerals? | Good electrical conductivity Good thermal conductivity High densities Malleability Ductility A metallic luster |
| What is electrical conductivity? | The ability of a material to conduct, or allow the movement through of electricity |
| What is thermal conductivity? | The ability of a material to conduct, or allow the movement through of heat |
| What is density? | The mass of a material in a defined volume and is measured in grams per cubic centimetre (sometimes reported as 'Specific Gravity'). |
| What are ductile metals? | Those that can be pulled out into a wire-like shape |
| What are malleable metals? | Those that can be hammered into other shapes without fracturing the material |
| What is the density of gold? | 19.3 |
| What is the density of copper? | 8.9 |
| What is the density of native silver? | 10.5 |
| What is the common base unit for mass? | The gram |
| 1000 g = 1 kg | 1000mg = 1g |
| 1 ounce = 28 grams | 16 ounces = 1 lb |
| Troy ounces ~31.1 grams | 12 troy ounces = 1 troy pound |
| What is the purity or fineness of gold described in? | In karats |
| 24 karat gold is what percent of gold? | 100% |
| Why is it rare to have 24 karat gold in jewellery? | Because pure gold is too soft |
| What karat does most jewellery have? | 14 karat gold |
| What is the non gold portion made up of in a less than 24 karat gold? | Silver / copper |
| Purity can also be described as what? | In percent |
| What is silver commonly measured in? | fineness - 1 = 100% pure siver |
| What is sterling silver made up of? | A standard alloy and is 92.5% Ag and 7.5% Cu. |
| What is the purity of platinum group measure on? | On a scale of 1 to 1000, with 1000 being pure |
| What is a carat? | Is the most common unit used for weighing gemstones. |
| Most minerals are what? | Chemical compounds....a few others occur as single native elements. |
| Do minerals have an electrical charge? | No |
| Out of 4000 common minerals how many are precious gemstones? | 50 |
| Minerals are usually formed by what process? | Inorganic processes |
| What does a chemical formula represent? | The chemical composition of a given compound or mineral |
| apfu | atoms per formula unit |
| What is diamonds chemical formula? | C |
| What is quartzes chemical formula? | SiO2 |
| What is pyrites (fool's gold) chemical formula? | FeS2 |
| All compounds must have what charge? | A neutral charge |
| Fayalite | Fe2SiO4 |
| The concept of charge neutrality is important in understanding what concept? | Elemental substitution of minor and trace elements into a given mineral |
| What do mineralogists and geoscientists often report the amount of a cation in? | Weight percent of its oxide form. |
| What is this way based on? | The methods used in chemical analysis. |
| The elemental constituents of a mineral can be broadly divided into three groups based on what? | Their relative abundance |
| Name the three groups? | Major, Minor and Trace elements |
| Major elements | - Are fundamental in a mineral's crystal structure and have a major impact on the resulting bulk properties. - They are always part of a mineral's chemical formula ex) Iron in Fe2SiO4. |
| Minor elements | -Are present in smaller amounts and commonly replace major elements in a mineral. -They are sometimes a part of a mineral's chemical formula. |
| Example of a minor element? | If there was just a little bit of magnesium in iron-dominated olivine (Fe > Mg)2SiO4, Mg would be considered a minor element |
| Trace elements | Are found only in very small amounts and can either be a replacement for one of the major elements in a crystal structure or can be occupying "holes" in a crystal structure that are big enough for them to hide in. |
| Are trace elements written in the chemical formula? | Very rarely |
| What are major elements reported in? | Always reported in weight percent of the oxide |
| What are minor elements reported in? | Usually reported in weight percent of the oxide |
| What are trace elements reported in? | Are almost always reported in parts per million (ppm) but an atom basis. |
| Why are trace elements reported in ppm? | To avoid long decimals and allow easier comparisons and interpretation of data |
| What is a chromophore? | Elements that cause colour in minerals |
| What amount are they found in? | Trace amounts |
| When the concentration of an element is very very low what is it reported in? | Parts per billion (ppb) on an atom basis. - Often for Gold. |
| What is olivine's chemical formula? | (Mg,Fe)2SiO4 |
| What mineral is produced when Mg is dominant in (Mg,Fe)2SiO4? | Forsterite |
| What mineral is produced when Fe is dominant in (Mg,Fe)2SiO4? | Fayalite |
| What phenomena is really important in mineralogy / mineral groups? | The phenomena of one element substituting for another. |
| What elements commonly switch for each other? | Minor and trace elements to substitute for major elements in a mineral |
| What is Goldilocks Principle? | Substitution between elements is only allowed because the cations of these two elements are pretty similar. (Based on their valence states / ionic radius) |
| What is emeralds chromophore? | Chromium (Cr) |
| What does Cr replace in emeralds to produce the green colour? | Substituting into the normally colourless mineral beryl. (Usually Al is a good match) |
| What is the chemical formula of beryl? | Be3Al2Si6O18 |
| What is the chemical formula of emerald? Why? | Be3Al2Si6O18 - same as beryl b/c Cr is a trace element and not included - |
| What is simple substitution? | When one element substitutes for just one other element. |
| What is coupled substitution? | When more than two elements are involved in substitution. |
| Why do these substitutions occur? | Because chemical compounds must remain charge neutral. |
| Name an example of a coupled substitution. | The replacement of Al (which has a +3 charge) in the mineral corundum (Al2O3) by a charge-balanced amount of Fe (+2 charge) and Ti (+4 charge) |
| What happens when Fe/Ti are added to corundum (Al2O3) | Becomes blue |
| What mineral does the substation of Fe/Ti to corundum Al produce? | Sapphire |
| What are the physical properties that help identify an unknown mineral? | Colour, Luster, Streak, Cleavage, Fracture,W Tenacity, Hardness, Refractive Index, Specific Gravity, Fluorescence |
| What is the colour in minerals caused by? | The absorption or refraction of light at particular wavelengths |
| Why does this happen? | B/c of diff trace elements or the absence of an atom or ionic radical that would normally occupy in a crystal |
| What is a vacancy? | When there is an absence of a colour or ionic radical from a point that would normally occupy in a crystal |
| What is the result of a vacancy? | A color center |
| What is the chromophore in the red ruby and green emerald? | Chromium (Cr) |
| What is the violet of fluorite produced by? | Vacancy |
| What is the colours of opal created by? | The arrangement of microscopic spheres of silica in its structure |
| What causes different colours of fluorite? | The presence of trace hydrocarbons |
| How can a diamond be identified? | 1. Unequaled hardness 2. Luster 3. Perfect cleavage 4. High refractive index |
| What is a mineral's luster? | The general appearance of its surface in reflected light. |
| Name the two types of luster. | 1. Metallic 2. Non-mettalic |
| Metallic luster | Luster of untarnished metal (gold, steel, copper) |
| Non metallic luster | Minerals --> generally lighter in colour / show some degree of transparency / translucency |
| What is vitreous? | Having the luster of a piece of broken glass |
| What is adamantine? | having the brilliant lustre of diamond |
| What is resinous? | Having the lustre of a piece of resin |
| What is pearly? | Having the luster of pearl |
| What is greasy? | Appearing to be covered in a thin layer of oil. |
| What us silky? | Having the appearance as the surface of silk or satin = no reflection |
| What is earthy | Having the non lustrous appearance of raw earth. |
| What is diagnostic streak? | The colour of the powder prodded when a specimen is drawn across a surface. (ex) unglazed porcelain) - far more consistent than colour |
| What streak is iron oxide hematite? | Red streak |
| What streak is iron oxide magnetite? | Black streak |
| What is cleavage? | The ability of a mineral to break along a flat planar surface |
| What is fracture? | The breaks of a mineral that occur in other directions than along the cleavage planes. |
| Hackly fractures w/ jagges edges often found where? | In metals |
| Shell-like conchoidal fractures are typical of what mineral? | Quartz |
| What is tenacity? | Term used for a set of physical properties: malleability, ductility or brittleness |
| What is hardness? | Is the relative ease or difficulty with which a mineral can be scratched - 1 to 10 |
| What mineral has a hardness of 1? | Talc |
| What mineral has a hardness of 10? | Diamond |
| What is refractive index? | The extent of the refract of light as it passes through a transparent or translucent mineral changing velocity or direction. |
| What is specific gravity? | A measure of density of a substance - ratio of the mass of the substance to the mass of an equal volume of water |
| What is fluorescence? | Minerals that emit visible light of various colours when subjected to ultraviolet light. |
| The nature of the physical properties of a mineral is directly related to what? | The mineral's chemistry |
| Minerals are what kind of substances? | Crystalline - They have a crystal lattice |
| What are the building blocks of a crystal called? | The unit cell |
| What are the 3D shapes of a crystal called? | Polyhedra |
| Name the four most common polyhedrons in minerals. | Tetrahedron, octahedron, cube, and icosahedron |
| What are tetrahedron, octahedron, cube, and icosahedron referred to as? | Platonic solids |
| What is each polyhedron typically composed of? | A central cation carrying a positive charge and surrounded by a number of anions carrying negative charges |
| What is X-fold coordination? | When these cations and anions are interacting with each other. |
| Tetrahedron | 4-fold coordination = four equal triangular-shaped sides. |
| Cubic | 8-fold coordination = six square-shaped sides, forming a cube. |
| Octahedron | 6-fold coordination |
| icosahedron | 12-fold coordination |
| What lustre does a diamond have? | Adamantine |
| Where did the first appreciation and mining of diamond occur? | India |
| In ancient India what characteristics of diamonds were most valued? | - Euhedral shape (e.g., octahedrons) - Fire (its dispersion of light) and brilliance |
| When did diamonds start to be faceted? | 13th century --> Venice or Antwerp |
| When could non-royalty individuals start wearing diamonds? | 17th century |
| This shift brought on the development of what? | The rose/table cuts were replaced with old cut |
| What was the old cut replaced by? | Brilliant cut (developed mathematically in 1919 by Tolkowsky) which is commonly seen today. |
| Describe the brilliant cut. | Designed to enhance the beauty, not power, of the stone and maximized the outward fire and brilliance of the diamond at the expense of total weight. |
| Vallerano Diamond | Found during excavations of a ~150 AD tomb in Vallerano, Italy |
| Historically where were diamonds found? | Extremely rare, sourced from only a few scattered alluvial (i.e., within river gravels) localities. |
| Where were diamonds first discovered? | The Golconda Region of India and then subsequently in Brazil by the 18th century |
| What is the max # of carats produced annually from India before the 18th century? | 50,000 carats |
| When could diamonds more commonly come into the hands of not only royalty but also the upper class? | With the discovery of kimberlite at Kimberly, SA in 1867 |
| What was the name of the establishment that faced the diamond mining in SA? | De Beers Consolidated Mines Ltd. in 1888 |
| What significantly changed the way diamonds are mined, polished, and sold? | The subsequent rise of competing diamond producers (Soviet Union in the 1950's, Australia in the 1980's and Canada in the 1990's) and the drive by consumers to ensure conflict-free diamonds. |
| Today what is De Beers production contribution? | 60% of global total |
| What does the Kimberly process monitor? | The import/export activity of participating countries, keeping tabs on legitimately mined and processed diamonds. |
| What % of the global diamond trade is sources form conflict zones? | 1% |
| How many carats of rough diamonds produced a year? | 170 million carats - 1 million of that is from conflict zones |
| How many carats does SA produce annually? | 15 million carats - 8% of global production |
| Mineralogically, what is a diamond? | Pure carbon that is packed into a dense crystalline structure (3.51 g/cm3) with cubic symmetry and perfect octahedral cleavage |
| What is diamonds hardness? | 10 |
| Diamonds refractive index? | 2.42 -exhibits great dispersion or splitting of light into a rainbow |
| What colour is a pure diamond? | Colourless |
| What allows diamonds to show the full range of colours in the rainbow? | -Various rare structural defects -Elemental substitutions -Laboratory procedures |
| Name the 4C's of diamonds | colour, cut, clarity and carat. |
| What crystal system does a diamond belong to? | Isometric or cubic crystal system |
| Isometric or cubic crystal system means... | That each of the crystallographic axes is the same length and at 90 degrees to one another - makes it hard / durable |
| What kind of cleavage does a diamond have? | Perfect cleavage - "octahedral" for its cleavage. - 8 sided polygon |
| The first subdivision in the scientist's classification scheme is based on what? | The amount of nitrogen (N) that has substituted into the crystal structure |
| Type I | More than 10 ppm N |
| Type II | Less than 10 ppm N - considered nitrogen free |
| Type I further divisions | 1. Type Ia where N atoms occur in clusters within the diamond 2. Type Ib where N in the diamond structure is dispersed |
| Type Ia further divisions | 1. Type IaA: N clusters in pairs 2. Type IaB: N clusters in quads |
| Type II further divisions | 1. Type IIa: no other impurities 2. Type IIb Boron as trace impurity, up to 10 ppm |
| What group do most diamonds belong to? | Type Ia group (98%) |
| What kind of light do Type Ia diamonds absorp / emit | Absorb blue light Show yellow hue |
| Next most common type of diamonds? | Type IIa (<2%) |
| What colour do type IIa diamonds show and why? | Due to a lack of impurities, these diamonds tend to show the whitest colour with little to no absorption of light across the visible spectrum |
| What can physical deformation / defects in Type IIa crystals give rise to? | Most pink, purple, and brown diamonds. |
| What is the rarest type of diamond? | Type IIb --> minute B but no N |
| What is the colour of type II b / why? | The incorporation of boron causes most light except blue to be absorbed, imparting a blue to grey hue. |
| Ex) of type IIb diamond | Hope diamond |
| Type Ib colors | Range in colours including yellow, brown, orange, and green or can be colourless |
| DeYoung Red Diamond carat, cut/ clarity? | 5.03, round brilliant cut and good clarity (Graded at VS2) |
| How many strongly coloured diamonds are found per year? | ~12 |
| Wittlesbach blue diamond carats/price? | 35.56 carats - $24.3 million USD, about ~$680,000 per carat |
| What is the external shape of any mineral controlled by? | Its internal arrangement of atoms |
| Diamonds have what kind of symmetry? | Cubic |
| Shapes can change the initial shape of any mineral through processes like... | Corrosion or abrasion. |
| What is the most common shape of a diamond? | Octahedrons (octahedron modified by cube faces, or cubes modified by octahedron faces) |
| What is Macles? | Uncommonly, diamonds may be twinned or show a flat tabular form |
| Diamonds sometime form... | polycrystalline (poly=many) aggregates and tend to be harder than monocrystalline (mono=one) specimens |
| What is a strong determining factor on diamond morphology? | The temperature at which a diamond grows |
| Higher temps yield what shape? | octahedral shapes |
| Shape of a diamond is also affected by... | The saturation conditions diamond grows in. |
| What happens under supersaturated conditions? | Diamond grow too fast resulting in cloudy crystals or fibre-like overgrowths. |
| Secondary modifications usually occur during what two distinct phases in a diamond's life? | 1. After growth but during transport to the Earth's surface by kimberlite magmas 2. During transport while on the Earth's surface. |
| First phase modifications? | Typically include corrosion of diamonds along preferential weaknesses that are prone to chemical attack |
| Second phase modifications? | Abrasion during river or alluvial transport |
| What are dirty diamonds called? | Bort |
| Bort is often used for what? | To impregnate the diamond discs that faceters use. |
| What do corrosive modifications during transport give rise to? | Rounded edges of primary crystal growths (which are usually octahedrons). The end product is a diamond with strongly rounded features almost approaching the shape of a beach ball |
| What about multiple growth and corrosion events? | Can lead to highly complex and intricate shapes. |
| What modifications are more major magmatic transport or alluvial? | Magmatic transport |
| What are the most common alterations result from processes on the Earth's surface (mainly mechanical abrasion)? | Scratched surfaces on the diamond or as abraded crystal edges |
| Name the properties that distinguish a diamond from other minerals. | 1. Hardness (no other mineral will scratch a diamond) 2. Thermal conductivity (most commonly used --> more conductive than copper) 3. refractive index 4. dispersion 5. its isometric/cubic optic nature -reflects water / sticks to grease - some will fluorescence under UV light |
| What are materials commonly used to imitate diamonds? | -Moissanite (higher dispersion, greater refractive indices, not isometric), -Cubic zirconia, glass, strontium titanite and yttrium-aluminum-garnet (lower thermal conductivity). |
| What do the treatments improve in the diamond? | Treated to improve their clarity and/or modify their colour |
| Where did diamond specific treatments originate? | In India well before the 2nd century BCE |
| What were the treatments in India? | Simple and likely consisted of coatings and dyes applied directly to the surface of the stone in order to neutralize an undesirable body colour (e.g., yellow/brown) or enhance a desirable one (e.g., blue). |
| What did Roman rings use? | Foil backings to give the stone an apparent colour |
| When did modern diamond treatments take off? | 1950's |
| What is the most famous treated colour diamond in the world? | The Deepdene diamond (currently 104.53 ct), which was irradiated and heated in 1955 to intensify its yellow hue |
| What are the modern diamond colour-altering techniques? | HPHT annealing (High pressure, High temperature) LPHT annealing (Low pressure, High temperature) Irradiation, |
| What colour altering technique is most common / important to use today? | HPHT annealing |
| What does irradiation do? | Create vacancies within the atomic lattice of diamond, which generate colour centers that can absorb light in the visible and near infrared portions of the electromagnetic spectrum |
| Early on what did irradiation expose the diamond to? | To the element radium, which imparted a blueish-green colouration into the stone. - take several months / only a small layer - leave detectable radioactivity |
| Neutron radiation | The defects (and therefore colour) were able to be imparted throughout the entire stone and leave no detectable radioactivity |
| How can green coloured diamonds be naturally produced? | If the stones are situated in proximity to certain minerals which emit natural radiation |
| What is HPHT annealing? | Technicians are able to increase the temperature of a diamond while maintaining a very high pressure, and preventing graphitization (conversion of diamond to graphite) of the stone. |
| What is the effects of HPHT annealing? | This has profound effects on the crystal structure with the ability to alter the combination states of nitrogen impurities (changing from Type Ia to Ib and vice versa) and "heal" lattice vacancies. |
| Colours can be produced by HPHT depends on what? | The starting type of diamond (e.g., Type I, Type IIa etc.) and the exact temperatures and pressures used, a wide variety of colours could be produced |
| What is the most common result of HPHT annealing? | -The removal of a brown body colour; and removing or enhancing an existing yellow colour. - Other colours such as blue, green, pink and yellow can be produced indirectly after the dominant brown colour is removed |
| What is LPHT? | Similar process to HPHT except that graphitization of the diamond is encouraged at low pressures. |
| Why is LPHT chosen? | For highly-flawed stones with numerous inclusions or fractures which are considered unsightly and thus, not very valuable. |
| What happens to the crystal structure during LPHT? | The crystal structure of diamond starts to change to graphite along fracture surfaces |
| What colour does LPHT produce? | An overall black/dark appearance to the stone, hiding the internal imperfections. |
| What combination of colour treatments are the most common and why? | - HPHT and irradiation - This gives researchers and technicians the ability to produce virtually the entire colour spectrum of diamond |
| What treatments are used to treat the stone's clarity? | Glass-filling, laser-drilling and acid boiling. |
| What is glass filling used for? | Used to fill in surface-reaching fractures and flaws which greatly improves the overall clarity of the stone. - glass needs to be an appropriate refractive index to cover the flaw |
| What kind of glass is used? | lead-bismuthate glass RI >2 |
| What is laser drilling? | Involves using a very high powered laser to drill into the diamond to reach inclusions that are otherwise sealed from the surface of the stone. |
| What is acid boiling? | Once an inclusion is reached, the diamond is put in a boiling acid bath which either bleaches or dissolves out the inclusion |
| What happens after acid boiling? | The resulting pit and drill hole are then filled in with glass. |
| Can a diamond be produced synthetically? | Yes, since the 20th century. |
| what are synthetic diamonds used for? | Produce small diamonds that were better suited for industrial applications |
| What are the two methods currently being used to grow gem quality diamonds? | Carbon Vapor Deposition (CVD) and High Pressure High Temperature growth (HPHT) |
| Name companies producing synthetic diamonds | Gemesis, Element Six, and Apollo |
| How big are the synthetic diamonds being produced? | - Usually 0.5 carat range - Rough sizes up to 25 carats |
| What does the HPHT growth method do? | Imitates the growth of natural diamond by creating an environment that is near 1,500 °C and 60,000 atm of pressure. - Small seed diamonds are placed in a chamber, which is then flooded with molten carbon and other metal catalysts. -The seed diamond crystals act as growing points (i.e., nucleation points) where C atoms attach to as the diamond grows. |
| The growth process of HPHT is ... and can produce.... | Fairly slow (1 carat /day) and can produce faceted crystals up to 1/2 carat. |
| What doe the CVD method do? | - conducted under low pressure - also uses a diamond seed crystal to act as a nucleating point for the new diamond |
| What is the key to CVD? | Is to flow hydrogen and methane gas (CH4 acts as the carbon source) through a chamber with a plasma flame in the flow path |
| What does the flow of hydrogen / methane gas do? | This effectively destabilizes the methane; carbon is then released and become available for attachment to diamond at the nucleating site. -Single crystals are grown by this method. After cutting, sizes reach just over ½ carat. |
| Diamonds occur in what kinds of deposits? | Primary and Secondary deposits |
| Where are primary deposits found? | Found in volcanic rocks both on the surface and in un-erupted magma that feed volcanoes |
| What are volcanic rocks that host diamond called? | kimberlite and lamproite |
| What are secondary deposits? | Include diamonds that have been moved from their primary source and concentrated in a new location. |
| What transports diamonds into secondary deposits? | Rivers and nearshore currents are the usual transport mechanisms |
| Where are diamonds stable at? | Only at great depths below the surface, where pressures are very high. |
| What is the required depth for the growth of a diamond? | At least 150 km |
| What temperature is required for a diamond to stabilize? | A"cool region" of between 900 and 1200 °C |
| What are Archean cratons? | These are a old collection of rocks (greater than 2.5 billion years), typically cool, and their great thicknesses push a keel down into the upper mantle |
| Where are diamonds favourable to grow? | At the base of this keel. - High pressure / cool temperatures |
| What is the diamond window? | The set of Pressure-Temperature conditions that define the diamond stability field |
| What is the stable mineral for pure C? | Graphite |
| What is the main mechanism to bring diamonds upwards? | Kimberlite magmas |
| Describe kimberlite magmas. | These magmas are generated at the base of the craton, ascend through the 150 km of crust very quickly, and then erupt in special volcanoes on the Earth's surface |
| How do kimberlite magmas collect diamonds? | The kimberlite magmas pick up diamonds that are in their pathway, then deposit them volcanically on the surface. |
| Why does this process have to be rapid? | In order to both prevent diamonds from transforming to graphite, as well bring them to the surface uncorroded. |
| Deep seated magma | Sourced from the upper mantle and is Fe- and Mg-rich + rich in K |
| What is ultramafic? | Fe- and Mg-rich |
| What is r ultrapotassic? | rich in K |
| What is barren kimberlite? | Kimberlite magmas generated away from diamond-bearing regions below the carton --> will never carry diamonds |
| What is the morphology of kimberlite volcanoes on the surface? | Ties to igneous nature + the nature of the rocks they are passing through. |
| What is a diatreme? | a vertical and carrot-shaped body of kimberlite volcanoes |
| How long are the diatremes across at the surface? | 1 km |
| What minerals commonly occur in diamond bearing kimberlites? | green olivine, purple pyrope garnet, chromium-bearing diopside, chromium-bearing spinel, and the iron titanium oxide, ilmenite. |
| What are the minerals listed above called? | Indicator minerals |
| What is the difference b/w lamproite and kimberlite? | - Lamproite commonly includes the mineral leucite while kimberlite does not - lamproites can exist in areas outside of Archean cratons, unlike most kimberlites |
| What mine produces diamond from lamproite rocks on a commercial scale? | The Argyle Diamond Mine in northern Australia |
| Why are diamonds rare? | Because their formational environment is well below the Earth's surface and only special geological conditions allow their transport upwards. |
| At the end of the 19th century where were diamonds only sourced from? | Alluvial deposits in India |
| How much carats of diamonds are produced annually? | Nearly 170 million carats |
| Where is Canada ranked in the world's top producer of diamonds? | 3rd = 14% of global production |
| How many mines does Canada have operating? | Four |
| Where was the first diamond bearing kimberlite pipe discovered? | In the Lac de Gras area in the Northwest Territories in 1991 = Ekati mine, owned by BHP Billiton |
| How much does the Ekati mine produce/ year? | 3 to 5 million carats annually |
| Diavik Diamond Mine opened when? | 2003 in NWT |
| How much is produced at the Diavik Diamond Mine? | 8 million carats annually |
| De Beers' Snap Lake Mine | Discovered in 1997, opening in 2008 located in NWT |
| De Beers' Snap Lake Mine prodution? | an expected ~1.5 million carats to be produced annually. |
| Victor Mine | De Beer owned, which is located in northern Ontario. - Began production in 2008 |
| Victor mine production? | Is expected to produce ~600,000 carats annually. |
| What sites are on the verge of becoming mines? | The Jericho and Gahcho Kué Diamond Mine projects. |
| Where are the majority of kimberlite rocks located in the Canadian shield? | Hosted in Archean Rocks older than 2.5 billion years |
| Current science at UBC for diamonds? | The Mineral Deposit Research Unit and the Diamond Research Laboratory |
| Who introduced the standardized 4C system? | De Beers in the late 1930's |
| What is the fifth C? | Country of origin. - Bears historical significance / the chance of it being a conflict diamond |
| What is cerussite? | A mineral that is a lead carbonate with particularly high average refractive index and dispersion. |
| What is the light of the desert? | A faceted cerussite PbCO3 from Namibia, 898 carats. |
| What can certain cuts do? | - maximize brilliance and fire - or to intensify colours |
| What is the most classic diamond shape seen today? | The Round Brilliant |
| How was The Round Brilliant cut designed? | Based on the physics of light and diamond, to return the most amount of light back up through the table of the stone. |
| Name some designer cuts. | "Hearts and Arrows", "Amore", "Arctic Empress" and "Star Cut" |
| The cut of a gemstone refers to what? | The quality of the facets that define its proportions. |
| The cut of a gemstone can have an effect on what? | - plays a very big role in the resulting optical effects of fire and brilliance - can also have a significant impact on the weight of a diamond |
| What will a stone with an excellent (ideal) cut show? | Good symmetry of facets as well as good Length to Width ratios when comparing the top-down dimensions of the table and full diameter. |
| What the factors for grading a cut? | Assessing the quality of the facets and their polish, looking at the physical proportions of the stone, girdle diameter and angles for the crown and pavilion. |
| What is clarity? | It describes the internal and external imperfections of a stone. |
| What are the most common flaws in a diamond? | Solid mineral inclusions |
| Other flaws? | - fluid-filled inclusions, clouds, feathers, or external features such as scratches, abrasions or burns |
| Clarity rankings | I (included) to FL (flawless). |
| What is the ideal colour of a diamond? | colourless |
| Almost all diamonds have what undertone colour? | Yellow |
| Range of colour scale | Starts from D, which is colourless, and ranges to Z, which is a fairly deeply-coloured yellow and considered undesirable. |
| When diamonds are beyond classification of Z they are termed what? | Fancy |
| What does fancy mean? | An indication that their colour is saturated enough to be unusual. |
| D/E/F | Colourless |
| G-J | near colourless |
| K-M | Faint color |
| N-R | Very light yellow colour |
| S-Z | Obvious light yellow colour. |
| One carat is equal to 0.2 grams | 5 carats is equal to 1 gram |
| What is a point? | 1 point is 0.01 carats. |
| Grading reports | The main physical properties of the graded diamond are clustered together in sets, and each diamond graded by the GIA receives a certificate number (This certificate number is engraved on the girdle of each diamond for identification purposes) |
| What is the rapaport? | The most commonly used summary of current diamond prices |
| What organization monitors the diamond industry and through what process? | World Diamond Council, formed in 2000 by The Kimberley Process. |
| Kimberly process targets reducing what? | Conflict stones |
| What is the kimberly process? | An agreement between the major diamond mining, exporting, and importing countries and companies. |
| How many countries are involved in the kimberly process? | 74 - US is very significant impact |
| What countries that do not comply with the kimberly process? | Cote d'Ivoire, Zimbabwe, and Venezuela |
| What is a flaw of the process? | Is more geared to monitoring large scale production from more significant sources (e.g., hard rock mines) and has difficulty addressing smaller artisanal scale operations. |
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