Kyanite

Kyanite is a typically blue aluminosilicate mineral. The name, used since 1789, is from the Greek (kyanos) meaning blue.  The French spelling, Cyanite, was commonly used by mineralogists through much of the 19^th and early 20^th centuries.  It is a common metamorphic silicate mineral and is one of the index minerals that are used to estimate the temperature, depth, and pressure at which a rock undergoes metamorphism.  It is a polymorph of andalusite and sillimanite – same chemistry, different crystal structures. At a specific pressure (0.4GPa) temperature (500ºC) range - the triple point - it is possible for all three mineral phases to co-exist.

ï  Mineral: Kyanite

ï  Chemistry:Al₂(SiO₄)O

ï  Class: Neosilicates

ï  Crystal system: Triclinic

ï  Color: Blue, white, light gray, green;  rarely yellow, orange, pink

ï  Streak: Colorless

ï  Refractive index:  1.710 – 1.735

ï  Luster: Vitreous, sub-vitreous, greasy, pearly

ï  Specific gravity: 3.53-3.67

ï  Mohs Hardness: 5.5 parallel to [001], 7 parallel to [100]

ï  Cleavage: Perfect; perfect on (100), good on (010)

ï  Fracture: Splintery

Kyanite is strongly anisotropic, in that its hardness varies depending on its crystallographic direction.  Blue Kyanite can be strongly trichroic - changing color based on crystal orientation –colorless/pale blue – greenish or violet-blue – dark blue.

Kyanite occurs in gneiss, schist, pegmatite, and quartz veins resulting from high pressure regional metamorphism of principally pelitic rocks.  It occurs associated with staurolite, andalusite, sillimanite, talc, hornblende, gedrite, mullite and corundum.  

Kyanite is used primarily in refractory and ceramic products.  It is also used in electronics, electrical insulators and abrasives.  Kyanite has been used as a semiprecious gemstone.

Specimens of Kyanite available at Taos Rockers are from Brazil.

Melody, in her book Love Is In The Earth,says “This is one of the few minerals in the mineral kingdom which never needs cleansing or clearing.  It will not accumulate or retain negative energy or vibrations.  The energy of Kyanite is unlimited in application, making it one of the very best attunement stones....It brings tranquility and a calming effect to the whole being…Kyanite Facilitates Meditation!...”