The close association of this mineral with cassiterite leads to its usefulness in locating tin-bearing pegmatites.
The close association of this mineral with cassiterite leads to its usefulness in locating tin-bearing pegmatites. Formed from the reaction of fluorine vapor with eutectic granites, where it occurs in cavities, its prismatic habit and orthorhombic crystallography derive from independent silica tetrahedra that cross-link its octahedral chains of aluminum hydroxide and fluoroxide. Named for a Red Sea island, FTP, what is this mineral with formula Al2SiO4(F,OH) and a Mohs Hardness of 7, the birthstone of November?
The close association of this mineral with cassiterite leads to its usefulness in locating tin-bearing pegmatites.
topaz