Mineral Groups

Major SilicatesMake up more than 90 percent of the

minerals in Earth’s crust

A compound of silicon, oxygen and usually one or more metallic elements, such as aluminum or iron

Silica tetrahedron structure, which is four oxygen atoms bonded to a central silicon atom

QuartzMade entirely of tightly bound silica tetrahedra.

Chemical formula SiO2

Glassy or greasy luster

Pure Quartz is colourless or white

Hardness of 7 on Mohs scale

Only second most abundant on Earth’s crust

FeldsparsMake up about 60 percent of Earth’s crust

Two directions of cleavage

Hardness of 6

Pearly luster

Some of the silicon atoms in the tetrahedral structure are replaced by aluminum

The net charge due to this exchange causes the addition of other metals (K, Na, and Ca)

Other SilicatesPyroxene

Mica

Amphibole

Kaolinite

Carbonate FamilyMade of negatively charged carbonate ions

(CO32-) bonded to positive metal ions

Limestone and marble consist almost entirely of carbonate minerals

Calcite (Calcium Carbonate) and dolomite (Calcium magnesium carbonate) are two examples

Oxide and Sulfide FamilyCombined with a iron

Not as common as silicates or carbonates, but very important economically

Examples are Hematite (most common iron oxide), Magnetite (black iron oxide), and Pyrite (most common sulfide mineral, iron sulfide)

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