Onyx
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About Onyx
Formula:
SiO2
Colour:
Black and white
Lustre:
Waxy
Hardness:
6½ - 7
Specific Gravity:
2.6 - 2.65
Crystal System:
Trigonal
Name:
From Greek ὄνυξ (onyx, "claw, fingernail"), presumably because onyx with flesh-coloured and white bands can resemble a fingernail.
In correct usage, the name refers to a (usually) black and white banded variety of agate, or sometimes a monochromatic agate with dark and light parallel bands (brown and white for example). Traditionally the name was reserved for black and white banded agate, and brown varieties named sardonyx.
The traditional method to make onyx is reported to have involved soaking the stone for months in honey or some sugar-rich solution, and then into concentrated sulphuric acid, which turned the sugar-infused bands black.
Note:
In recent times the name has become confused with other banded materials. In particular banded calcite formed in cave systems such as the material found in Mexico and Pakistan and often carved, in fact the majority of carved material (such as book-ends, chess-sets, etc.) that are available today are made from this carbonate rock. This is a carbonate material and not true onyx. Other names have been used over time for this material, such as "Mexican onyx" and "onyx-marble". Careless use of these names has resulted in the term 'onyx' being incorrectly applied to a variety of banded materials that are not covered by the original definition of the name.
Visit gemdat.org for gemological information about Onyx.
The traditional method to make onyx is reported to have involved soaking the stone for months in honey or some sugar-rich solution, and then into concentrated sulphuric acid, which turned the sugar-infused bands black.
Note:
In recent times the name has become confused with other banded materials. In particular banded calcite formed in cave systems such as the material found in Mexico and Pakistan and often carved, in fact the majority of carved material (such as book-ends, chess-sets, etc.) that are available today are made from this carbonate rock. This is a carbonate material and not true onyx. Other names have been used over time for this material, such as "Mexican onyx" and "onyx-marble". Careless use of these names has resulted in the term 'onyx' being incorrectly applied to a variety of banded materials that are not covered by the original definition of the name.
Visit gemdat.org for gemological information about Onyx.Unique Identifiers
Mindat ID:
2999 (as Onyx)
3337 (as Quartz)
3337 (as Quartz)
Long-form identifier:
mindat:1:1:2999:1 (as Onyx)
mindat:1:1:3337:0 (as Quartz)
mindat:1:1:3337:0 (as Quartz)
Physical Properties of Onyx
Waxy
Transparency:
Translucent, Opaque
Comment:
Vitreous when polished
Colour:
Black and white
Comment:
often produced by dying agates
Streak:
White
Hardness:
6½ - 7 on Mohs scale
Fracture:
Conchoidal
Density:
2.6 - 2.65 g/cm3 (Measured)
Comment:
varies with amount and type of impurities
Chemistry of Onyx
Mindat Formula:
SiO2
Elements listed:
Crystallography of Onyx
Crystal System:
Trigonal
Synonyms of Onyx
Other Language Names for Onyx
Common Associates
Associations Based on Photo Data:
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Onyx
mindat.org URL:
https://www.mindat.org/min-2999.html
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References for Onyx
Localities for Onyx
Showing 50 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Afghanistan | |
| Vikhter et al. (1976) +1 other reference |
Argentina | |
| Tauber (2015) |
| Peña (1970) +1 other reference | |
| Raúl J. Tauber Larry´s collection (2014) | |
| Peña (1970) | |
Australia | |
| Fetherston et al. (2013) |
| Gemstones of Western Australia +5 other references |
| Fetherston et al. (2013) |
Brazil | |
| Revista Brasileira de Geociências |
| Strieder et al. (2006) |
Canada | |
| Simandl et al. (1998) |
China | |
| Zhimin Cao (1991) |
| Tang (2005) |
Czech Republic | |
| geological prospecting |
Falkland Islands | |
| Aldiss et al. (1999) | |
France | |
| OLLIC Pascal Collection |
Germany | |
| Weiß (1990) |
| Weiß (1990) |
| Wittern (2001) |
| Wittern (2001) |
India | |
| Richard M. Pearl: "Minerals of India" |
| Richard M. Pearl: "Minerals of India" |
Madagascar | |
| Behier (1963) |
Russia | |
| Polekhovsky et al. (2008) |
Serbia | |
| Miladinović et al. (2016) |
| Miladinović et al. (2016) |
Spain | |
| Manuel et al. (2018) |
UK | |
| |
USA | |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| Eckel et al. (1997) |
| - (2005) |
| Ransom (1974) |
| - (2005) |
| - (2005) |
| Ariel S Wall |
| AmMin 11:334-340 |
| Roberts et al. (1965) |
| Bullock (1981) |
| - (2005) |
| Bullock (1981) |
| Bullock (1981) |
| Bullock (1981) |
| Bullock (1981) | |
| Bullock (1981) | |
| - (2005) | |
| Dietrich (1990) |
| Dietrich (1990) | |
| Hausel et al. (2001) |
Hunedoara County, Romania