MINERALS• WHAT ARE THEY??

MINERALS

• The basic materials of the earth’s crust.

• The “building blocks” of rocks

• Thousands are known

• But only about 20 are common in the crust – these are the rock-forming minerals.

WHAT MAKES SOMETHING A MINERAL??

1) Must be “inorganic” – not made from living (or once-living) things.

2) Must occur naturally (not made by people).

3) Must be a solid, “crystalline” material.4) Must have a “definite chemical

composition”.

4 THINGS NEEDED:

For example – Here’s a piece of granite rock, and the three minerals that it is made of.

SO – WHICH OF THESE ARE MINERALS?

CONCRETE GOLD COAL

STEEL SALT (HALITE) OIL

SO – WHICH OF THESE ARE MINERALS?

CONCRETE GOLD COAL

STEEL SALT (HALITE) OIL

NO!! YES!! NO!!

NO!!YES!! NO!!

TWO MAIN GROUPS OF MINERALS1) SILICATES (96%)

Contain silicon (Si) and oxygen (O), plus other elements, usually

2) NON-SILICATES (4%)

6 major groups – see pp. 158-159silver gypsum

pyrite

quartz mica feldspar

USES OF MINERALS WE IDENTIFIED

# MINERAL FORMULA USES/NOTES

1 Muscovite Mica KAl2Si3O10(OH)2 Insulator, used for windows in olden days

2 Dolomite CaMg(CO3)2 Cement, limestone

3 Biotite Mica K(Mg,Fe)3AlSi3O10(F,OH)2

(approximate)Insulator

4 Halite NaCl Salt5 Calcite CaCO3 Main limestone

ingredient

6 PbS for lead7 Gypsum CaSO4 Wallboard

8 Graphite C Pencils, lubricant

USES OF MINERALS WE IDENTIFIED

9 Quartz SiO2 Glass manuf., electrical equipment

10 Talc Mg3Si4O10(OH)2 Used in paper production, baby powder

11 Magnetite Fe3O4 Ore for iron

12 Plagioclase Feldspar

(Ca,Na)Al(Al,Si)Si2O8 Glass, ceramics

13 Hematite Fe2O3 Ore for iron

14 Orthoclase Feldspar

KAlSi3O8 Ceramics, very common

15 Pyrite FeS2 “Fools Gold”, ore for sulfur