Kyanite (Cyprine)

Pale blue kyanite (also known as cyanite or disthene) is reported to lose its color on heating to 1200�C (Smith et al, 1978) - Nassau (1984) 4 to 7Walter Schumann, Gemstones of the world (2001) 4 - 4.5 along axes; 6 - 7 across axesMore from other references 3.55 to 3.70Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references BrittleWalter Schumann, Gemstones of the world (2001) PerfectUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references SplinteryArthur Thomas, Gemstones (2009) 1.710 to 1.735Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Biaxial/+,-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references 0.012 to 0.033Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Blue stones - strong trichroism: colorless/pale blue - (greenish or violet)-blue - dark blueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references 0.020Arthur Thomas, Gemstones (2009) RareHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Blue, blue-green, green, brown, yellow, red, colourlessUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references Blue, Fe2+-O-Ti4+ charge transfer, Fe2+-O-Fe3+ charge transfer, Fe2+ and Fe3+ in octahedral coordination can all be involved, with contribution from Cr3+ in octahedral coordination. Green, V3+ in octahedral coordination; Fe3+ in octahedral coordination. Orange, Mn3+. Color change, Cr3+ in octahedral coordinationW. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) Transparent,TranslucentWalter Schumann, Gemstones of the world (2001) More from other references Vitreous,PearlyArthur Thomas, Gemstones (2009) More from other references Weak; redWalter Schumann, Gemstones of the world (2001) Blue: usually reddishHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references TriclinicHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Often fibrousHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Kyanite occurs in gneisses and schists and in granite pegmatites.Michael O?Donoghue, Gems, Sixth Edition (2006) Kyanite information at mindat.org Kenya  Natural History Museum Vienna collection Madagascar  Madagascar - extraLapis English No.1, p. 92 Mozambique  Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 422 USA  E.Ya. Kievlenko (2003) Geology of gems, p. 70