Mineral Families

Carbonates, phosphates, sulfates, oxides, sulfides, native elements

- basic structure and economic importance

Silicates are the most abundant mineral group, and because of their structure, the most varied and complex of the mineral groups. However, their are several other economically important and common mineral families:

Other mineral families:

Carbonates (CO3)2-

The three most common carbonate minerals are calcite, aragonite, and dolomite. These minerals are the components of limestones, a type of rock that covers large regions on the continents.

Limestones are important economic minerals. Limestones are used as building stone, in cements, as fertilizers, in the metal industry for flux, and in the chemical industry.

Phosphates (PO4)2-

The most important phosphate mineral for us is a calcium fluorine phosphate called apatite - Ca₅F(PO₄)₃. Apatite is secreted by vertebrate organisms to construct bones and teeth. Why do you think you brush with fluoride?

Inorganic apatite is mined as an important source of agricultural fertilizer.

Sulfates (SO4)2-

The two most common sulfates are the closely related calcium sulfates anhydride and gypsum. Both are formed from the evaporation of seawater. Gypsum is an important economic mineral because of its use in plaster and wall board materials.

Ore minerals: sources of economically useful elements. An ore is any rock or mineral that contains enough of an economically important mineral or element that it can be profitably mined.

Simple oxides

Because they are directly bonded to oxygen, with no silicon added, these minerals have useful elements in high concentrations.

Perhaps the most important oxides are the iron oxides like magnetite (Fe3O4) and hematite (Fe2O3). These form our principle iron ores.

The mineral Corundum (ruby) is a simple oxide of aluminum - (Al₂O₃). At very high temperatures, corundum crystals will form in masses of molten alumina, allowing the manufacture of synthetic ruby and other corundum gemstones.

Sulfides

Sulfides are similar to oxides, except it is the sulfur atom that forms the anion instead of oxygen. These minerals also form economically important ores like

Chalocopyrite is a copper ore. In the late 1800âs Siderite was mined as an iron ore

Often sulfides have a very metallic luster.

Pyrite, the iron sulfide, is not mined for iron (iron oxides are much better ores for this) but for sulfur, which is extracted and used in the chemical industry for making sulfuric acid. Gold may also exist as an "impurity" associated with pyrite.

Galena, a lead ore, can contain significant amounts of silver as an impurity. Thus it can be an important ore of silver.

Finally, sometimes elements are found in their pure form as mineral deposits. These are called Înative elementsâ and in the case of precious metals, they are the most sought after mineral deposits in the world.

Native Copper, Native Silver, Native Gold

Of course, there are other more obscure mineral groups, but these are neither abundant, nor economically important.

Halite - simple ionic compound

Fluorite -Fluorite is a calcium fluoride mineral

Used as a source of fluorine for hydrofluoric acid, for the manufacture of milk glass, as a flux for the steel industry, and in the refining of aluminum