USA, Mexico, Brazil, Switzerland, Sri Lanka, Burma, Madagascar, Color: colorless, light yellow, light pink, Hardness: 7, Refractive index: 1.63 1.64, Density: 2.98 3.03, Chemical composition: Ca(B2Si2O8), Crystal structure: orthorhombic, Origins: USA, Mexico, Brazil, Germany, Switzerland, Sri Lanka, Burma, Madagascar, Japan. Colorless danburites are common, with light pink or yellowish stones being more rare and expensive. Only eye clean pieces are valuable.
Southern and central Africa, Orange, blue, Orange, blue
Yellow, Brown, Colorless, White, gray, Brownish, Yellow
White, Blue
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
Irregular, Irregular, Gemstones of the world (2001)
CaB 2(SiO 4) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
CaCO 3Ulrich Henn and Claudio C.