Sardonyx
Sardonyx is a brown and white banded variety of onyx primarily used in glyptography.
Antique Victorian Sardonyx Seal Fob.
Gemological Information for Sardonyx
| Color: | Brown and White Layers |
| Crystal Structure: | Hexagonal (Trigonal) |
| Refractive Index: | 1.535 to 1.539 |
| Durability: | Good |
| Hardness: | 6.5 to 7 |
| Family: | Chalcedony |
| Similar Stones: | Dyed Onyx |
| Treatments: | Dyeing, Heating |
| Country of Origin: | Brazil |
Sardonyx Care
| Ultrasonic Cleaning: | Usually Safe (Watch for Glued Together White and Brown Cameo Imitations) |
| Steam Cleaning: | Usually Safe |
| Warm Soapy Water: | Safe |
| Chemical Attack: | Attacked by Hydrofluoric Acid and Nitric Acid May Remove Dye |
| Light Sensitivity: | Stable |
| Heat Sensitivity: | May Alter Color |
Sources
- Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 45-48.
- Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 269.
- Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 142.