Indicolite (Blue Tourmaline)

Routinely heat-treated to lighten the color - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 5 7 to 7.5Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) 3.05 to 3.11Michael O?Donoghue, Gems, Sixth Edition (2006) BrittleMichael O?Donoghue, Gems, Sixth Edition (2006) PoorMichael O?Donoghue, Gems, Sixth Edition (2006) 1.614 to 1.666Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Uniaxial/-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) 0.014 to 0.040Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Strong: dark blue - light blueWalter Schumann, Gemstones of the world (2001) 0.017Walter Schumann, Gemstones of the world (2001) (Dark)-blueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Blue, Fe2+ in octahedral coordination with possible influense of some iron related transfer processesW. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) Transparent,Translucent,OpaqueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) VitreousArthur Thomas, Gemstones (2009) Weak or noneWalter Schumann, Gemstones of the world (2001) TrigonalHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Prismatic to acicular crystalsMichael O?Donoghue, Gems, Sixth Edition (2006) Indicolite information at mindat.org Afghanistan  Bowersox and Chamberlin (1995) Bowersox and Chamberlin (1995) Glas (2002) Glas (2002) Brazil  Cassedanne and Roditi (1996) Cassedanne and Roditi (1996) Cassedanne and Roditi (1996) Menezes (2009) Mozambique  Henn and Bank (1997) Henn and Bank (1997) Schafer and Arlt (2000) Namibia  Schneider and Seeger (1992) Mossman (2002) Schneider and Seeger (1992) Pakistan  Laurs et al. (1998) Sri Lanka  USA  Fisher et al. (1999) Fisher et al. (1999) Jahns, R. H. and Wright, L. A. 1951. Gem and Lithium-bearing pegmatites of the Pala District, San Diego County, California. California Division of Mines special report 7A. Laurs (2001, 2002, 2004) Freeman (2005)