Smoky quartz
Description
A transparent dark gray or brown Quartz, also called cairngorm. Smoky quartz is found in Switzerland, Scotland (Mt. Cairngorm), Russia, Iran, Brazil, Sri Lanka and the U.S.(Colorado, California). It is sometimes used as a Gemstone. Most early uses of the stone date from Hellenistic times or later; one earlier example was found in Iran c 3250 BCE (Odgen 1982).
Synonyms and Related Terms
smokey quartz; cairngorm; Cairngorm stone; Rauchquarz (Deut.); quartz fumé (Fr.); quartzo fumado (Port.); rookkwarts (Ned.)
Physical and Chemical Properties
- Trigonal crystal system
- Low birefringence (0.009)
- Low thermal expansion
- Fracture = conchoidal
- Luster = vitreous to greasy
- Streak = white
- Fluorescence = generally inert
- Pleochroism = very weak with different tones of body color
- Heat-treatment can bleach the stone and may turn it yellow.
| Composition | SiO2 |
|---|---|
| Mohs Hardness | 7.0 |
| Density | 2.65 g/ml |
| Refractive Index | 1.544; 1.553 |
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
- Encyclopedia Britannica, http://www.britannica.com Comment: "smoky quartz." Accessed: 21 Jan. 2005 .
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia: Smoky quartz (Accessed Sept. 14, 2005 and Dec 2022)
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997