Realgar
China
7.46 carats
© Rarestone.com
Realgar forms red to orange-yellow prismatic crystals or granular masses. The crystals disintegrate to a powder after long exposure to light. However, this process takes a very long time. Realgar specimens should be kept in the dark, in an eclosed container.
Realgar is a very rare gem. It is very soft and somewhat unstable.
Realgar 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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| General Information | ||||||||||||||||
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| Chemical Formula |
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| Physical Properties of Realgar | ||||||||||||||||
| Mohs Hardness | 1.5 to 2, Gems, Sixth Edition (2006) | |||||||||||||||
| Specific Gravity | 3.56, Gems, Sixth Edition (2006) | |||||||||||||||
| Tenacity | Brittle,Sectile, Handbook of mineralogy (2001) Sectile, also slightly brittle | |||||||||||||||
| Cleavage Quality | Good, Handbook of mineralogy (2001) | |||||||||||||||
| Light Sensitivity | Disintegrate to a powder after long exposure to light, Gems, Sixth Edition (2006) | |||||||||||||||
| Optical Properties of Realgar | ||||||||||||||||
| Refractive Index | 2.538 to 2.704, Gems, Sixth Edition (2006) RI for the alpha, beta and gamma rays is 2.538, 2.684 and 2.704 | |||||||||||||||
| Optical Character | Biaxial/-, Gems, Sixth Edition (2006) | |||||||||||||||
| Birefringence | 0.166, Gems, Sixth Edition (2006) | |||||||||||||||
| Pleochroism | Nearly colorless to pale golden yellow, Handbook of mineralogy (2001) | |||||||||||||||
| Dispersion | Very strong, Handbook of mineralogy (2001) | |||||||||||||||
| Colour | ||||||||||||||||
| Colour (General) | Red to orange-yellow, Gems, Sixth Edition (2006) More from other references | |||||||||||||||
| Transparency | Transparent, Gems, Sixth Edition (2006) More from other references | |||||||||||||||
| Lustre | Greasy, Gems, Sixth Edition (2006) More from other references | |||||||||||||||
| Crystallography of Realgar | ||||||||||||||||
| Crystal System | Monoclinic, Gems, Sixth Edition (2006) | |||||||||||||||
| Habit | Prismatic, Gems, Sixth Edition (2006) More from other references | |||||||||||||||
| Geological Environment | ||||||||||||||||
| Where found: | Most commonly as a low-temperature hydrothermal vein mineral associated with As–Sb minerals; also as volcanic sublimations and in hot spring deposits; in carbonate and clay. sedimentary rocks, Handbook of mineralogy (2001) | |||||||||||||||
| Further Information | ||||||||||||||||
| Mineral information: | Realgar information at mindat.org | |||||||||||||||
| Significant Gem Localities | ||||||||||||||||
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