Onyx
(Reguidit frae Sardonyx)
Onyx is a bandit variety o chalcedony. The colours o its bands range frae white tae almaist every colour (save some shades, sic as purpie or blue). Commonly, specimens o onyx contain bands o black an/or white.
| Onyx | |
|---|---|
 A slice o sardonyx (width = 2.5 cm) | |
| General | |
| Category | Oxide mineral |
| Formula (repeatin unit) | Silica (silicon dioxide, SiO2) |
| Creestal seestem | Trigonal, Monoclinic |
| Identification | |
| Formula mass | 60 g / mol |
| Colour | Various |
| Cleavage | Absent |
| Fractur | Uneven, conchoidal |
| Mohs scale haurdness | 6–7 |
| Skinkle | Vitreous, silky |
| Streak | White |
| Diaphaneity | Translucent |
| Speceefic gravity | 2.65–2.667 |
