ABSTRACT
A mineral is a naturally occurring inorganic substance which has a definite chemical composition, normally uniform throughout its volume. Two techniques are employed to identify minerals: the study of a hand specimen and the examination of a thin slice. Examination of rocks in thin section will provide excellent details of rock textures, some of which are difficult to see in the hand specimen. The most obvious difference visible in hand specimens between two minerals in a rock is often that one is light coloured and the other is dark coloured. The common rock-forming minerals are formed mainly of combinations of the important elements such as oxygen, silicon, aluminium, iron, calcium, sodium, potassium and magnesium and most of them are silicates. Most minerals can be cleaved along certain specific crystallographic directions which are related to planes of weakness in the atomic structure of the mineral.
