Geology 10
Plummer S90
Minerals

You will need to identify the following minerals (or mineral groups) based on their physical properties. Diagnostic properties follow the mineral names.

Quartz- Harder than 5 1/2 (knife, nail, glass)
No cleavage (irregular fracture)

Feldspar- Harder than 5 1/2
2 directions of cleavage at right angles.
Usually white, pink or grey

Micas- 1 direction of perfect cleavage (easily pulled apart into sheets).
NOTE: Biotite is a mica as well as a ferromagnesian mineral.

Ferromagnesian minerals- Green or black. Lumped into this group are biotite,amphibole, pyroxene, olivine (you need not tell them apart in this course).

Calcite- Hardness of 3 (between a fingernail and a knife).
3 directions of cleavage not at right angles (rhombohedral).

Additional Information you need to know about minerals

Calcite is the only non-silicate mineral you need to know about now. It is calcium carbonate (CaCO3).

All of the silicates have Si and O, and additional elements as listed below.

Quartz is pure silica and a framework silicate.

The feldspar group is the most common in the crust. All contain Al as well as silica and:
plagioclase contains Ca and Na.
Potassium feldspar (or orthoclase) contains K.

The mica group are sheet silicates. All contain Al, K, H2O.
biotite also contains Fe, Mg.

The clay group minerals are sheet silicates.

"Ferromagnesians" all contain Fe, Mg. In addition to biotite:
pyroxene group are single chain silicates
amphibole group are double chain silicates
olivine is an isolated silicate mineral.