Onyx gemstone information (original) (raw)
Russia
3.81 carats
© Brian Kosnar - Mineral Classics
Layer stone with the combination of a black base and a white upper layer, also called true onyx or Arabic onyx. Onyx is also a name sometimes used for unicolored Chalcedony (e.g., black onyx).
The name Onyx has its origin in the Greek language and means "fingernail", probably because of its weak transparency.
Onyx Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
Onyx Gemstones by Size
This table shows distribution of Onyx 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
Average:3.66 cts
Total photos:4
3.55ct to 3.58ct3.58ct to 3.60ct3.60ct to 3.63ct3.63ct to 3.65ct3.65ct to 3.68ct3.68ct to 3.71ct3.71ct to 3.73ct3.73ct to 3.76ct3.76ct to 3.78ct3.78ct to 3.81ct
| General Information | |
|---|---|
| A variety or type of: | Agate, which is a variety of Chalcedony, which is a variety of Quartz |
| Onyx Treatments | |
| Black chalcedony ("onyx") is assumed to be dyed - Blue Chart Gem Identification, Herve Nicolas Lazzarelli, 2010, p 7 | |
| Physical Properties of Onyx | |
| Mohs Hardness | 6.5 to 7Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
| Specific Gravity | 2.55 to 2.70Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Optical Properties of Onyx | |
| Refractive Index | 1.530 to 1.543Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) |
| Optical Character | Uniaxial/+Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
| Colour | |
| Colour (General) | Straight color bands (black with white layer)Herve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
| Transparency | OpaqueHerve Nicolas Lazzarelli, Blue Chart Gem Identification (2010) More from other references |
| Crystallography of Onyx | |
| Crystal System | TrigonalUlrich Henn and Claudio C. Milisenda, Gemmological Tables (2004) |
| Further Information | |
| Mineral information: | Onyx information at mindat.org |
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