Kyanite from Brazil, hand polished

The mineral kyanite is an aluminum silicate having the chemical formula Al2SiO5. It belongs to the group of nesosilicates. Blue, gray, white, green or black mineral has perfect cleavage according to the crystal surface [100], a white stripe coloring and a glass for pearl luster. The crystal system is triclinic, the average density is 3.61 and the hardness is from 4 to 7. Kyanite is neither magnetic nor radioactive. The name of the mineral kyanite is derived from the Greek word Kyanos that "blue" means. Kyanite mineral is a very common as a part of many rocks. It is partly for in metamorphosed sedimentary rocks. It is also, along with the other aluminum silicates, sillimanite and andalusite a mineral indicative for the depth and temperature at which a rock has undergone transformation. Kyanite is usually stable at temperatures below 650 ° Celsius and at pressures higher than 0.3 GPa (giga pascal). The pressure and temperature are related so that at high pressure (0.6 GPa) has a higher temperature (600 ° C) is necessary to be formed from kyanite sillimanite. At pressures below 0.3 GPa is correct andalusite stable aluminum. Kyanites of gem quality are found in India, in the gemstone marketing creations in Myanmar and Korea. In the United States are kyanieten recovered in California, Tennessee, Georgia, New Hampshire, and North Carolina. Africa comes to kyanite in Kenya, Tanzania, in Europe in Russia, Switzerland, Austria and France. Kyanite occurs in the sand fraction of Dutch Quaternary river sediments. In the heavy-mineral analysis as in the Netherlands at the Geological Survey took place during the second half of the twentieth century, the mineral is assigned to the so-called stable group. In this study used only the name dist go.