General Information |
---|
Chemical Formula | Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
---|
Physical Properties of Grandidierite |
---|
Mohs Hardness | 7.5Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Specific Gravity | 2.85 to 3.00Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Cleavage Quality | DistinctUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
---|
Fracture | UnevenArthur Thomas, Gemstones (2009) |
---|
Optical Properties of Grandidierite |
---|
Refractive Index | 1.578 to 1.639Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Optical Character | Biaxial/-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Birefringence | 0.037 to 0.039Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Pleochroism | Distinct: greenish blue - colorless - blue-greenHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Colour |
---|
Colour (General) | Bluish-green, blueUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
---|
Transparency | TranslucentUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
---|
Lustre | VitreousArthur Thomas, Gemstones (2009) |
---|
Fluorescence & other light emissions |
---|
Fluorescence (General) | InertHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
---|
Crystallography of Grandidierite |
---|
Crystal System | OrthorhombicHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Habit | Elongated anhedral crystalsMichael O’Donoghue, Gems, Sixth Edition (2006) More from other references |
---|
Geological Environment |
---|
Where found: | Grandidierite occurs in aluminous boron-rich rocks and in pegmatites.Michael O’Donoghue, Gems, Sixth Edition (2006) |
---|
Inclusions in Grandidierite |
---|
Needle-like channels, parallel growth planes - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 6 |
Further Information |
---|
Mineral information: | Grandidierite information at mindat.org |
---|
Significant Gem Localities |
---|
| Madagascar | |
| Gems, Sixth Edition, Michael O’Donoghue, 2006, p.414 |
|
|