Kornerupine
India
1.20 carats
© Mineral Classics
Kornerupine was named after a Danish geologist and explorer A. N. Kornerup.
The colour can vary from brown, green to shades of yellow, the material is strongly pleochroic and frequently asteriated (from Burma and Taita Hills, Kenya). Cat's eye effect is due to inclusions of
rutile and
graphite.
Kornerupine can be faceted or cut into cabochons. Cut stones are up to 20 carats (usually to 3 carats).
General Information |
---|
Chemical Formula | Walter Schumann, Gemstones of the world (2001) More from other references |
---|
Physical Properties of Kornerupine |
---|
Mohs Hardness | 6.5Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Specific Gravity | 3.25 to 3.45Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Cleavage Quality | GoodWalter Schumann, Gemstones of the world (2001) More from other references |
---|
Fracture | ConchoidalArthur Thomas, Gemstones (2009) |
---|
Optical Properties of Kornerupine |
---|
Refractive Index | 1.660 to 1.685Herve 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 | 0.012 to 0.017Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Pleochroism | Strong trichroism is common for green variety: green - yellow - reddish brownHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Dispersion | 0.018Arthur Thomas, Gemstones (2009) |
---|
Chatoyancy | Rare star 4Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
---|
Colour |
---|
Colour (General) | Green, blue-green, brownish-green, greenish-brownUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
---|
Causes of Colour | Blue, Cr3+ in octahedral coordination. Green, V3+ in octahedral coordinationW. William Hanneman, Pragmatic Spectroscopy For Gemologists (2011) |
---|
Transparency | TransparentUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) More from other references |
---|
Lustre | VitreousArthur Thomas, Gemstones (2009) |
---|
Fluorescence & other light emissions |
---|
Fluorescence (General) | Usually none; green kornerupine from Kenya: yellowWalter Schumann, Gemstones of the world (2001) More from other references |
---|
Crystallography of Kornerupine |
---|
Crystal System | OrthorhombicHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Habit | PrismaticMichael O’Donoghue, Gems, Sixth Edition (2006) More from other references |
---|
Geological Environment |
---|
Where found: | Occurs in boron-rich volcanic and sedimentary rocks subjected to metamorphismMichael O’Donoghue, Gems, Sixth Edition (2006) |
---|
Inclusions in Kornerupine |
---|
Common needle-like inclusions: sharp cat's eye (grayish, greenish, black)- Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 4
Needle-like crystals, zircons with tension cracks - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 19 |
Further Information |
---|
Mineral information: | Kornerupine information at mindat.org |
---|
Significant Gem Localities |
---|
| Australia | |
- Harts Range (Harts Ranges; Hartz Range; Hartz Ranges)
| | | Greenland | |
| | | Kenya | |
| Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 421 |
| Collection of NHM, Vienna | | Madagascar | |
| Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 421 | | Myanmar | |
| |
| Ted Themelis (2008) Gems & mines of Mogok |
| Gems, Sixth Edition, Michael O’Donoghue, 2006, p. 421 |
- Pein-Pyit (Painpyit; Pyan Pyit)
| Ted Themelis (2008) Gems & mines of Mogok | | Sri Lanka | |
| |
| |
|
|