Spessartine
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Spessartine garnet; image credit Rob Lavinsky, iRocks.com
Description
A Garnet composed of manganese aluminum silicate. The color of spessartine may range from an orange-yellow to brownish-red. Gem quality stones are mined in Germany, Malagasy Republic, India, and the United States (Colorado and Maine). Historically, spessartine gemstones are rare but a few have been found dating to the 2nd and 3rd century BCE (Odgen 1982).
Synonyms and Related Terms
garnet; spessartite; espesartina (Esp;); Spessartin (Deut.); spessartien (Ned.)
Physical and Chemical Properties
- Isometric crystal system with massive to crystalline habit
- Cleavage = none
- Fracture = conchoidal
- Luster = vitreous to resinous
- Streak = colorless to white
- Fluorescence = inert
- Birefringence = none
| Composition | 3MnO-Al2O3-3SiO2 |
|---|---|
| Mohs Hardness | 6.5 - 7.5 |
| Density | 4.15 g/ml |
| Refractive Index | 1.800-1.810 |
| Dispersion | 0.027 (weak fire) |
Comparisons
Properties of Common Gemstones
Resources and Citations
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Wikipedia: Spessartine (Accessed Dec 2022)
- Jack Ogden, Jewelry of the Ancient World, Rizzoli International Publications, New York, 1982.
- Mineralogy Database: Spessartine
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 354
- Encyclopedia Britannica, http://www.britannica.com Comment: "spessartine." Accessed 20 Sept. 2005 .
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998