Classification, Distribution and Uses of Ores and Ore Deposits - Metals and Society: An Introduction to Economic Geology - page 21

Table 2.1 (continued)
Class Element Mineral Composition

Corundum Al 2 O 3

Grenat Silicate of Al, Mg, Fe

Talc Phyllosilicate

Mica Phyllosilicate

Diatomite and Clay

Alusite, kyanite Al 2 SiO 5

Albite NaAlSi 3 O 8

Halite NaCl

Calcite CaCO 3

2.1.2 Classifications Based on the Type of Mineral

The type of mineral provides the basis of classification given in Table 2.2 . Here we
see that a wide range of important metals are mined in the form of sulfide (e.g. Cu as
chalcopyrite, Pd as galena, Ni as pentlandite). Another important class are oxides,
which are mined for tin, as in the mineral cassiterite (SnO 2 ), or Fe in magnetite
(Fe 3 O 4 ) and uranium in pitchblende (UO 2 ). Other types of metals are found as
carbonates or sulfates, usually in alteration zones overlying primary deposits.
Very few metals are mined in their native form, the only common examples
being gold and the platinum-group elements. Carbon is also mined as a native
element as diamond or graphite, and in an impure form as coal. Although copper
does occur as a native metal, its occurrence in this form is usually more an
impediment than an advantage; although native copper does contain 100% Cu
and its presence boosts the copper grade, the mineral in malleable and tends to
gum up the crushing machines which are designed for brittle sulfides and silicates.
Silicates, by far the most important rock-forming mineral, are uncommon in the
list of ore minerals. Exceptions are garnierite, a clay-like mineral that is the major
ore mineral in Ni laterites; zircon (ZrSiO 4 ), a heavy detrital mineral mined for the
high-technology metal zirconium; and garnet, which is used as an abrasive. Quartz
is becoming increasing important as a source of the silica that

is used in

semiconductors and in solar panels.

Box 2.1 Copper, a Highly Versatile Metal
Copper, along with gold, was one the first metals to be used by mankind and it
is very widely used today. It is mined in almost all parts of the world, and it is
used very widely in industry. The major copper producing countries are Chile,
USA, Peru and China. Almost every country is a consumer of copper, the level
depending on the size of the population and the extent of industrialization.
(continued)