It includes their
formation, composition, characteristics, properties and identification.
And also some
information on mineral crystals.
Are Minerals Formed?
form in a few different ways. They form when magma
higher up where temperatures and pressures decrease, starts to freeze,
and mineral crystals form. They also form when a rock is metamorphosed
due to deformation, or high temperatures and/or pressures and new
composition of a mineral depends on the conditions in which it formed.
Because chemicals all strive to be stable, where conditions such as
temperatures and pressures change, chemical reactions start happening,
and new minerals are formed - with chemical compositions that are more
stable in the new conditions.
Mineral crystals are solids with an atomic system with a
repetative, three-dimensional pattern. The flat surfaces are
called crystal faces. They all have a certain symmetry, and they belong
to one of the crystal systems such as cubic, hexagonal, monoclinic,
orthorhombic, triclinic etc. They are also characterised by crystal
forms and habits.
Crystals, their systems, forms, structure and habits are some of mineral
Others include cleavage and fracture (how they break); hardness (how
hard they are when scratched); specific gravity (what they weigh in
water); luster (how they feel to touch); whether they are transparent;
and their colour and the colour of their powder - streak.
Mineral information also includes their specific properties.
minerals for example are
magnetic. Others react with certain acids (e. g. carbonates react with
HCl). Others conduct electricity (obviously the metallic ones). Yet
others may be slightly radioactive. And certain minerals are
involves checking the crystals, their habits and system; and checking
the other characteristics and properties such as streak, colour,
transparency and luster; and checking its hardness, fracture, cleavage
and specific gravity. Is it magnetic? Does it react to HCl? Once the
characteristics and properties are checked, easier minerals can be
identified without using any tables or charts. With more complicated
identification charts can be used.