are solids with a definite (mostly inorganic) chemical composition which
are formed by natural processes. They are extremely important to the
geologist as they form the 'building blocks' of rocks. So far, approximately
3500 distinct mineral species have been discovered and authenticated,
although each year a few more new minerals are added to this list. Minerals
can exhibit a bewildering variation in chemical composition, crystal
form, colour, size and other physical properties; some of the more attractive
minerals will be familiar to many people because their fine colours
and reflective properties allow us to use them in jewellery and other
ornamental materials. However, to the geologist, minerals are also extremely
important because through the study of their occurrence, formation,
properties and use (the subject of mineralogy) we gain an important
insight into how a rock may have formed. The type of information we
can derive is varied, for instance:
- was the
rock formed deep in the Earth or at a shallow depth?
- was the
rock once molten or did it form from an aqueous fluid?
- did it
form at high or low temperatures?
- has it
been weathered or otherwise altered after it first formed?
it have some economic value?
are also crucial in our everyday life as they are the source for a wide
range of substances; you only need to take a quick look around to see
how much material has been derived from minerals in the Earth. Such
materials include metals (for example gold, copper and iron), materials
for the chemicals industry (salt, fertiliser, sulphur), ceramics (clay)
and construction (calcite for cement, gypsum for plaster). Each year
we need more and more of these to satisfy our increasing demands, yet
future deposits are either becoming increasingly hard to find or are
located in areas where mining may conflict with other activities. It
is the role of the geologist and earth scientist to discover the resources
for the future and to ensure that they can be exploited in the most
efficient and environmentally friendly way possible.
shown here are of some representative minerals, including the form in
which they occur, and some important aspects associated with their extraction.