Magnesite

Dyed to imitate lapis, turquoise (chelsea: common reddish), coral. Acetone test - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 8 3.5 to 4.5Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references 2.92 to 3.12Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references PerfectUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references ConchoidalArthur Thomas, Gemstones (2009) 1.509 to 1.720Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references Uniaxial/-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references 0.190 to 0.202Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) DoublingMore from other references NilArthur Thomas, Gemstones (2009) NilArthur Thomas, Gemstones (2009) White, yellow, brown, black, colourlessUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references Translucent,OpaqueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references Vitreous,DullWalter Schumann, Gemstones of the world (2001) More from other references Blue, green, white commonHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) Blue green or white fluorescence may be seen with greenish phosphorescenceMichael O?Donoghue, Gems, Sixth Edition (2006) GreenishHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) TrigonalHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references MassiveMichael O?Donoghue, Gems, Sixth Edition (2006) More from other references Magnesite occurs as a primary mineral in igneous or sedimentary rocks or may be formed by the metamorphism or alteration of serpentine and peridotite.Michael O?Donoghue, Gems, Sixth Edition (2006) Magnesite information at mindat.org Brazil  Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 426 Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 426