TOPAZ Chemische Eigenschaften,Einsatz,Produktion Methoden
Definition
topaz: A variably coloured aluminiumsilicate mineral,Al
2(SiO
4)(OH,F)
2, that forms orthorhombiccrystals. It occurs chieflyin acid igneous rocks, such as granitesand pegmatites. Topaz is valuedas a gemstone because of its transparency,variety of colours (the wineyellowvariety being most highly prized), and great hardness (8 on theMohs’ scale). When heated, yellow orbrownish topaz often becomes arose-pink colour. The main sources oftopaz are Brazil, Russia, and the USA.
TOPAZ Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte