1. Minerals
An Introduction

2. Minerals: what are they?
A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure and a definite chemical composition.
Yes, this means that coal is not a mineral.

3. How minerals form
Crystallization from magma: crystals form as the temperature drops below their melting points; iron, calcium, magnesium minerals solidify first, sodium, potassium, and aluminum at lower MP.
Examples:
Feldspar (used for ceramics)
Quartz (used for glass manufacture)
Muscovite (common white Mica)
Hornblende

4. How minerals form Precipitation: minerals are dissolved in water
Common minerals:
Halite (NaCl), which we know as salt
Gypsum (CaSO4·2H2O)
Calcite (CaCO3)

5. How minerals form
Pressure and temperature: some minerals form when preexisting minerals/rocks are subjected to high temperatures and pressures.
Examples:
Garnets in schist
Chlorite

6. How minerals form
Hydrothermal solutions: high temperature solutions ( C) flowing through existing minerals/rocks, dissolve and reform into new minerals.
Examples:
Quartz (SiO2)
Pyrite (FeS2)

7. Mineral Groups
There are over named, indentified minerals, and they are broken into groups; here are some of them:
Silicates: minerals with a framework of silicon and oxygen; they are the most numerous group.
Carbonates: very common; usually a salt of a metal and the carbonate ion: CO3-2.
Oxides: usually metals that have reacted with oxygen
Sulfates and sulfides: metals that reacted with sulfur, some further reacted with oxygen/water/solutions
Halides: minerals where metals have reacted with halogens (group 7A)
Native elements: some elements that are found without having reacted with another element: Gold, Silver, Copper, Sulfur, Carbon (diamond, graphite)

8. Mineral Properties
Each mineral has its own unique set of characteristics.
Color
Streak: color in a powdered form or when rubbed against an unglazed white tile
Luster: reflection/sheen
Crystal form: showing the internal crystal lattice in an external form
Hardness: a relative scale: Mohs
Cleavage: tendency to break along flat surfaces
Fracture: when mineral do not cleave, the type of broken surface that does occur.
Density/specific gravity: ratio of a mineral/substance’s mass to its volume.
Others: feel (talc: greasy)