Sardonyx
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Description
A red color Onyx, which is an Agate with parallel bands of Chalcedony. Sardonyx has layers of brownish Sard alternating with lighter-color layers of red Carnelian. Often used as a gemstone, it has been mined or gathered since before 2200 BCE.
Synonyms and Related Terms
onyx; quartz; agate; chalcedony
Physical and Chemical Properties
- Fracture = conchoidal, uneven
- Luster = vitreous to waxy
- Streak = white
- Mohs Hardness = 6.5 - 7.0
- Density = 2.6 g/ml
- Fluorescence = generally inert
- Pleochroism = absent
- Refractive Index = 1.530 - 1.543
Comparisons
Properties of Common Gemstones
Resources and Citations
- Mineralogy Database: Quartz
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- Wikipedia: Onyx varieties Accessed Dec 2022
- A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979