1. What Are Minerals?

Minerals
3. How are minerals made?
Minerals grow in a wide variety of geological environments - salt lakes, deep
oceans, volcanoes, and cooling deep masses of molten rock. They can also grow
under the influence of heat and/or pressure, and from solutions and gases carrying
concentrations of certain elements. Usually, minerals grow when solutions or gases
rich in certain elements cool or evaporate, molten rock cools, or heat and/or
pressure change (re-organise) pre-existing chemicals.
4. How do we identify minerals?
Some minerals are instantly recognizable because of their unique colour or shape,
but usually some simple non-destructive tests can be done to prove the identity of
the most common minerals present. These tests include those for the crystal system
(based on symmetry), colour, lustre, transparency, cleavage, fracture, streak colour,
refractive index, ultra-violet fluorescence, magnetism, radioactivity, specific
gravity, melting (fusion) and simple chemical tests. Sometimes more complex tests
are necessary, involving complex and expensive analytical instruments which use
X-rays, such as the X-ray Diffractometer (analyses crystal structure) and Electron
Microprobe or Energy Dispersive Spectrometer (analyses chemical contents).
5. Mineral Classification by Chemical Composition
Minerals are categorized according to their chemical composition or "mineral
class". There are eight mineral classes which are categorized by anion (negative
ion) group.
5.1. Class 1: Native elements
Apart from the free gases in the Earth’s atmosphere, some 20 elements occur in
nature in a pure (uncombined) or nearly pure form. Known as the native elements,
they are partitioned into three families: metals, semimetals, and non-metals.
The most common native metals, which are characterized by simple crystal
structures, make up three groups: the gold group, consisting of gold, silver, copper,
and lead; the platinum group, composed of platinum, palladium, iridium, and
osmium; and the iron group, containing iron and nickel-iron. Mercury, tantalum,
tin, and zinc are other metals that have been found in the native state.
The native semimetals are divided into two isostructural groups (those whose
members share a common structure type): (1) antimony, arsenic, and bismuth, with
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