Kyanite (blue variety Dist)
Habitat: Austria, France, Italy, Macedonia, Russia
Basic information: Crystallises in the triclinic system, crystals usually have elongated columnar, fibrous or bladed habit. Frequent twins and radial aggregates. It occurs mainly in the regional metamorphic pegmatites rocks at high pressure. Secondary is in the drifts.
Moh’s scale hardness is 4.5-5 parallel with one axis and perpendicular to that axis is 65-7 (anisotropic property). That is the most useful characteristic in identifying kyanite.It has very good cleavage and splintery fracture. Transparent or partially transparent. Kyanite has white streak and vitreous luster and pearly glow.
Other information: The name comes from the Greek word Kyanos meaning blue.
Due to the high resistance to high temperatures it is used in the production of refractory ceramic and porcelain, electronics and fine transparent specimens to produce jewelry.