Brief Description: Its name derives from the terms pyr (fire) and iron. The term pyrite in the ancient times referred partially to a ferrous and partially to a copper ore (source: Dioskourides and Plinius). It was believed that it contained fire, which was released as bright sparkles when it was hit. Until 1800, the terms pyrite and marcasite referred to the minerals iron pyrite, marcasite, chalcopyrite, arsenopyrite and magnetopyrite. It has the chemical formula FeS2 and it belongs to the category sulphurous minerals. Its lustre is glossy metallic, while its colour ranges from yellow, light brass to golden-yellow. Many times, it becomes darker from surface oxidation colours and is iridescent. Opaque. It has specific gravity 5.0, while its hardness ranges from 6 to 6.5 (and it is very high for a sulphide) and its fusibility is 2.5 - 3.0. It usually occurs in the form of cubic crystals. Also, in pentagonal dodecahedra and octahedra. The cubes and the pentagonal dodecahedra often bear lines. It also occurs in solid, granular, botryose and stalactite-like aggregates. It usually deteriorates into limonite and goethite forming frequent pseudomorphs by iron pyrite. It constitutes the most spread sulphide. It can be found in all types of geological environments. It connects with other minerals and mainly with galenite, sphalerite, chalcopyrite, calcite, quartz, siderite, rodochrosite etc. It is mainly used to make sulphuric acid, which is applied in chemical industry, fertilizers manufacture, metallurgy and oil cleanup. It is also used to make iron sulphate, which is applied in paint making, ink industry, wood maintenance, disinfectants etc. 
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