Minerals and Rocks
|mineral||a solid, naturally-occuring obj w/a defined chemical composition. inorganic w/a crystalline structure, the building blocks of rocks|
|silicate|| silicon plus oxygen or silicon dioxide (SiO2), Quartz and feldspar group silicates make up most|
of Earth's continental crust
|non-silicate||Many important mineral groups are not silicates.These include the carbonates, oxides, halides, sulfides, sulfates, and native metals. |
The non-silicate groups are a source of many valuable ore minerals and building materials.
To be an ore, a mineral must occur in large enough quantities to be economically recoverable.
|Rock|| A rock is a naturally formed consolidated solid mixture|
containing minerals, rock fragments, or volcanic glass
The terms igneous, sedimentary, and metamorphic refer
to how a rock was formed.
|Igneous||Made up of magma or lava|
|Sedimentary||Made from sediments|
|Metamorphic||Rocks changed by pressure or heat|
|intrusive|| Igneous: Formed from magma which cools and solidifies|
below Earth's surface
Cooling and solidification take a long time resulting in large visible crystals
Coarse-grained like granite
Granite is mostly found in the continents
|extrusive|| Formed from lava on or above Earth's surface|
Cooling and solidification takes place relatively quickly resulting in very small crystals
Fine-grained like basalt
Basalt is in the ocean floor
|classification of intrusive igneous rock|| Rocks that are quartz-rich and contain|
potassium feldspar and plagioclase feldspar
are called granite.
Rocks with no quartz and abundant
plagioclase feldspar and pyroxene are called
|classification of extrusive igneous rock||These rocks may have the same compositions as intrusive|
igneous rocks, but they always will have different textures.
Composition of the surrounding rock material will also
affect the extrusive magma.
A magma rich in silica (SiO2) forms rhyolite if it cools rapidly.
Similarly, gabbro's fine-grained volcanic counterpart is
basalt, which is a common rock in Earth's oceanic crust. If cooling starts off slowly below the surface with large
crystals, but then finishes at a faster rate to form small or
no crystals, the extrusive rock is called porphyry.
|foliated||A texture in metamorphic rock which has lots of layers or bands|
|Nonfoliated||A texture in metamophic rock that has grains in more random orientations|
|Physical properties||a mineral has characteristics, a set of physical properties, but some of these properties can differ from sample to sample: cleavage, fracture, luster and streak, crystal shape, and hardness|
|Atom arrangement||The arrangement of atoms and the bonds between them can reflect the way a mineral breaks, how hard it is, and what types of crystal shape it has.|
|Cleavage|| Minerals break along planes that cut across|
relatively weak chemical bonds, a smooth, flat
surface is created.
Most minerals (except metals) have one or
more cleavage planes that also help in
determining their identity.
|Fracture|| irregular break|
Some minerals do not split along well-defined
In such cases, a mineral will break unevenly.
|Hardness|| resistance to scratching|
use Mohs hardness scale- Friedrick Mohs 1812
whether a mineral can scratch another mineral
|Luster and Streak|| The way a mineral reflects light, whether it looks metalic or non-metalic...glassy or earthy(dull) or waxy|
Sreak: color of min. in powdered form
|Crystal Shape||Controlled by arrangement of atoms, look at types of symmetry|
|porosity||When clasts are loose on Earth's surface, they don't fit together perfectly. The empty space in between the grains|