Black Opal
Ethiopia
8.55 carats
© gemselect.com
Black opal is rarer than White opal.
Black Opal Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
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Black Opal Gemstones by Size
This table shows distribution of Black Opal gemstone sizes that are listed on this site. This can give a good indication as to the general availability of this gemstone in different sizes.
Contributed photos
Lightest:1.34 cts
Heaviest:20.04 cts
Average:7.44 cts
Total photos:18
Do you have a larger Black Opal? Why not upload a photo?
| General Information | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| A variety or type of: | Precious Opal, which is a variety of Opal | |||||||||||||||||||
| Chemical Formula |
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| Synthetic Black Opal | ||||||||||||||||||||
| Light-coloured opals can be darkened using several methods to simulate Black opals. - Opal, Lithographie, 2007 | ||||||||||||||||||||
| Physical Properties of Black Opal | ||||||||||||||||||||
| Mohs Hardness | 6 to 6.5, Blue Chart Gem Identification (2010) | |||||||||||||||||||
| Specific Gravity | 1.97 to 2.22, Gemmological Tables (2004) | |||||||||||||||||||
| Tenacity | Brittle, Gemstones of the world (2001) | |||||||||||||||||||
| Cleavage Quality | None, Gemstones of the world (2001) | |||||||||||||||||||
| Fracture | Conchoidal, Gemstones (2009) | |||||||||||||||||||
| Optical Properties of Black Opal | ||||||||||||||||||||
| Refractive Index | 1.370 to 1.470, Blue Chart Gem Identification (2010) | |||||||||||||||||||
| Optical Character | Isotropic, Gemstones (2009) | |||||||||||||||||||
| Birefringence | None, Gemstones of the world (2001) | |||||||||||||||||||
| Pleochroism | Absent, Gemstones of the world (2001) | |||||||||||||||||||
| Dispersion | None, Gemstones of the world (2001) | |||||||||||||||||||
| Colour | ||||||||||||||||||||
| Colour (General) | Dark background colour, Management Team (2012) | |||||||||||||||||||
| Transparency | Transparent,Translucent,Opaque, Gemmological Tables (2004) | |||||||||||||||||||
| Lustre | Vitreous, Gemstones (2009) | |||||||||||||||||||
| Crystallography of Black Opal | ||||||||||||||||||||
| Crystal System | Amorphous, Blue Chart Gem Identification (2010) | |||||||||||||||||||
| Habit | Massive, Gemstones (2009) | |||||||||||||||||||
| Further Information | ||||||||||||||||||||
| Mineral information: | Black Opal information at mindat.org | |||||||||||||||||||
| Significant Gem Localities | ||||||||||||||||||||
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