Rocks and Minerals:

Rocks and Minerals:

A mineral is a naturally occurring, inorganic solid with a definite chemical composition and a specific crystalline structure; where as a rock is an aggregate of one or more minerals. As rock consists of number of minerals, one or few minerals may be major constituents in a particular rock. When a particular rock formation, as per major minerals present, has economic value for extraction of a certain metal or group of metals, that rock is called ‘ore’ of that metal. These ores can be later undergo metallurgical processes for extraction of metal. For example, Iron ore; a rock formation that has minerals compound of iron element, and iron (Fe) content is such that can be economically extracted in a steel plant.

Commercially valuable minerals and rocks are referred to as industrial minerals. Therefore, ores (i.e., commercially valuable minerals and rocks are referred to as industrial minerals or ore) must have economic value for extraction of a metal or group of metals or for a certain product. As these ores / rocks are obtained naturally on the earth crust, for ultimate use these are mined, i.e., taken out from earth – by opencast or underground process, as per the mode of availability.

A mineral can be identified by several physical properties. Most common physical properties or structure used for identification purpose is:
(1) crystal structure;
(2) physical hardness;
(3) luster;
(4) color;
(5) streak;
(6) cleavage;
(7) specific gravity etc.

More complex way and accurate way to determination of minerals is X-ray diffraction.