Ch 4 Minerals

STUDY
PLAY

Terms in this set (...)

Mineral - The 5 characteristics of minerals
MUST have ALL 5 of the following or the substance is not a mineral:
1. Naturally occurring (Is found in nature. Doesn't need to be made in a lab)
2. Inorganic (Never was alive)
3. Solid (Has definite shape & volume)
4. Specific chemical composition (Specific ratio)
5. Crystalline structure
Crystal
A solid in which atoms are arranged in repeating geometric patterns. (Note, well-defined crystal shapes are not seen unless they form slowly and in an open space.)
Magma
Molten material found beneath the Earth's crust.
Large crystals formed when magma cools slowly far beneath earth's surface.
Small crystals formed when magma cools quickly close to earth's surface or due to volcanic eruption (as lava) and contact with air or water.
Supersaturated Solution
Solution = Liquid mixture (Liquid with something dissolved in it)
Supersaturated = Mixture has more dissolved than normally possible.
Leads to crystal formation - crystals "precipitate" out of solution and become solid.
Example: As salty water evaporates, salt is left behind.
Trace elements
Very small amounts of an extra element can change the color of mineral, but NOT the streak color.
Example: Quartz can be clear, yellow, pink, or purple depending on what extra element is present.
Luster
The way a mineral reflects light from its surface.
The 2 main categories are metallic or non-metallic.
Texture
How a mineral feels.
Examples: smooth, rough, soapy, glassy
Streak
The color a material leaves when it is rubbed across a porcelain plate.
MORE DEPENDABLE than color of the mineral itself, because the streak color is constant.
Can only be used when the mineral is softer than the plate.
Hardness
The measure of how easily a material can be scratched. Compared to Moh's Hardness Scale, 1-10. Harder minerals will scatch softer materials. Softer minerals cannot scratch harder minerals.
Cleavage
The ability of a material to break easily and evenly along a flat plane.
Fracture
The type of edges formed when a material breaks into pieces. Various types of fractures include minerals that expose arclike, rough, non-smooth or jagged edges.
Silicates
Mineral that contains silicon & oxygen. Examples: Quartz & feldspar. Most common mineral group; 96% of minerals in the crust are silicates.
Ferromagnesian
Dark colored silicates due to high amounts Iron (Fe) and Magnesium (Mg).
Examples: Olivene, Pyroxene, Biotite, Amphibole.
Non-ferromagnesian
Light colored silicates due to high levels Silicon and Oxygen, and very low amounts of Iron or Magnesium.
Examples: Quartz, Feldspar, Muscovite
Carbonates
Mineral made of carbon, oxygen (CO3) & 1 metal.
Example: Calcite. Found in rocks such as limestone & marble.