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Introduction
| Mainly composed of zinc and sulphur, sphalerite often contains iron, manganese and other minerals. Its optical properties vary with the amount of iron contained. As the amount of iron increases, its color will change gradually from colorless to light yellow, brownish yellow and brown while the white streaks will turn brown.The amount of iron contained in sphalerite is closely related to the temperature at which it is formed. The higher the temperature, the more iron-rich and darker the sphalerite will become. On the other hand, the lower the temperature, the less iron and lighter in color. Iron-rich sphalerite can be divided into two subspecies: marmatite (Fe>8-10%) and black sphalerite (Fe~26%).Sphalerite can be commonly found in hydrothermal sulphurous veins and it tends to be intergrown with galena. Sphalerite is used not only as a major ore of zinc but also a major source of scarce elements such as Cd, Ga, Ge, In and Tl. |
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