A mineral is a naturally occurring organic and inorganic substance, having an orderly atomic structure and a definite chemical composition and physical properties. A mineral is composed of two or more elements. But, sometimes single element minerals like sulphur, copper, silver, gold, graphite etc. are found. There are at least 2,000 minerals that have been named and identified in the earth crust; but almost all the commonly occurring ones are related to six major mineral groups that are known as major rock forming minerals. Some major minerals and their characteristics: Feldspar: Silicon and oxygen are common elements in all types of feldspar and sodium, potassium, calcium, aluminium etc. are found in specific feldspar variety. Quartz: It is one of the most important components of sand and granite. It consists of silica. It is a hard mineral virtually insoluble in water. Pyroxene: Pyroxene consists of calcium, aluminum, magnesium, iron and silica. Pyroxene forms 10 per cent of the earth’s crust. Amphibole: Aluminium, calcium, silica, iron, magnesium are the major elements of amphiboles. They form 7 percent of the earth’s crust. Mica: It comprises of potassium, aluminium, magnesium, iron, silica, etc. It forms 4 per cent of the earth’s crust. Olivine: Magnesium, iron and silica are major elements of olivine. It is used in jewellery. It is usually a greenish crystal, often found in basaltic rocks. Metallic Minerals: These minerals contain metal content and can be sub-divided into three types: Precious metals, Ferrous metals Non- ferrous metals.