Anatase
Brazil
6.25 carats
© Rarestone.com
Anatase is named after Greek "anatasis" - extension, alluding to the greater length of the common pyramid as compared to other tetragonal minerals.
Anatase is polymorphous with
rutile and
brookite. It is very similar to
rutile in lustre, hardness and density, but differs in its crystal habit and cleavage. When exposed to high temperature anatase transforms into
rutile.
Rare transparent specimens are faceted into brilliant gems.
General Information |
---|
Other Names/Trade Names: | |
---|
Chemical Formula | Michael O’Donoghue, Gems, Sixth edition (2006) More from other references |
---|
Photos of natural/un-cut material from mindat.org |
---|
|
Physical Properties of Anatase |
---|
Mohs Hardness | 5.5 to 6Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Specific Gravity | 3.82 to 3.97Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Cleavage Quality | PerfectArthur Thomas, Gemstones (2009) |
---|
Fracture | Sub-ConchoidalArthur Thomas, Gemstones (2009) |
---|
Heat Sensitivity | SensitiveArthur Thomas, Gemstones (2009) |
---|
Optical Properties of Anatase |
---|
Refractive Index | 2.488 to 2.562Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Optical Character | Uniaxial/-Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Birefringence | 0.073Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Pleochroism | Orange/brown stones - distinct: yellow - orangeHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
---|
Dispersion | Ord - 0.213 to Ext - 0.259Arthur Thomas, Gemstones (2009) |
---|
Colour |
---|
Colour (General) | Dark brown, colourless, yellow, blue, reddish, black.Walter Schumann, Gemstones of the world (2001) More from other references |
---|
Transparency | Transparent,TranslucentHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Lustre | AdamantineWalter Schumann, Gemstones of the world (2001) More from other references |
---|
Fluorescence & other light emissions |
---|
Fluorescence (General) | InertHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
---|
Crystallography of Anatase |
---|
Crystal System | TetragonalHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
---|
Habit | Usually as bipyramidsMichael O’Donoghue, Gems, Sixth edition (2006) More from other references |
---|
Geological Environment |
---|
Where found: | Anatase results from the alteration of other titanium-bearing minerals and is also found in hydrothermal veins.Michael O’Donoghue, Gems, Sixth edition (2006) |
Further Information |
---|
Mineral information: | Anatase information at mindat.org |
---|
Significant Gem Localities |
---|
| Myanmar | |
| Ted Themelis (2008) Gems & mines of Mogok |
|
|