(1) Apatite. It is a compound of Calcium phosphate. It is red, brown, yellow or green. Phosphorous and Fluorine is obtained from it.
(2) Barite. It is Barium Sulphate. Its relative density is 4.5. It has a white or brown colour. It has a pearly lustre. It occurs in granular of crystalline masses. It is used in glass, rubber-chemical.
(3) Bauxite - It is non-crystalline soft and occurs in small pellets. lt is an Hydrous Oxide of Aluminium. In pure form it is white and brown. It is also red, yellow and brown if there is an impurity of iron in it. Aluminium is obtained from it.
(4) Calcite - it is calcium carbonate. It is white or colorless. It is an important ingredient of limestone, chalk and marble.
(5) Chlorite - it is hydrous Magnesium Iron. Aluminium, Silicate, like Mica crystals, it has cleavages but unlike Mica it is non-flexible. It is of green colour.
(6) Cinnabar - It is Mercury Sulphide. It is soft, heavy, deep red or brown. Mercury is obtained from it.
(7) Corundum - It is Aluminium Oxide. It is hard, heavy, brown or light blue and has six sided crystals. Examples- Ruby, Gem and Sapphire.
(8) Dolomite - It is a double carbonate of Calcium and Magnesium. It is white. It is used in making cement and is also used in Iron and steel industries.
(9) Galena - It is Lead Sulphate. It is black, brittle, heavy and occurs in cubes. Lead is obtained from it.
(10) Gypsum - It is hydrous Calcium Sulphate. It is soft, white or colorless and pearly in crystals. Many idols and objects of arts are made of it.
(11) Haematite - It is red oxide of Iron. It is found in sedimentary rocks. Iron is obtained from it.
(12) Kaolinite - It a known as China clay. It is hydrous Aluminium silicate. It is found in light colors. In the wet condition, it is plastic and can be converted into my shape. It is used for making paper, china clay, tiles and crockery.
(13) Magnesite - It is white and non-crystalline. It is known as Magnesium Carbonate. It is used as refractory material in furnaces.
(14) Magnetite - It is black Iron Oxide. It is found in igneous rocks. Iron is obtained from it.
(15) Pyrite - It is Iron Sulphide. It is hard, yellow and brittle, Iron and sulphuric acid are obtained from it.
(16) Talc - It is hydrous Magnesium Silicate. It is soft, soapy, white or brown or light yellow. It is used in making paints, rubber, crockery, roofs, paper, plastic and insecticide.
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