Difference between revisions of "Andradite"
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| Line 11: | Line 11: | ||
* Fracture = conchoidal | * Fracture = conchoidal | ||
| − | * Luster = vitreous to resinous | + | * Luster = vitreous to resinous |
| − | * Streak = colorless | + | * Streak = colorless |
| − | |||
* Dispersion = 0.057 | * Dispersion = 0.057 | ||
| − | * Pleochroism = none | + | * Fluorescence = inert |
| − | * | + | * Pleochroism = none |
| + | * Birefringence = none | ||
{| class="wikitable" | {| class="wikitable" | ||
| Line 40: | Line 40: | ||
* Mineralogy Database: [http://www.webmineral.com/data/Andradite.shtml Andradite] | * Mineralogy Database: [http://www.webmineral.com/data/Andradite.shtml Andradite] | ||
| − | + | * Gem Identification Lab Manual, Gemological Institute of America, 2016. | |
* G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971 | * G.S.Brady, ''Materials Handbook'', McGraw-Hill Book Co., New York, 1971 | ||
| − | |||
* ''Encyclopedia Britannica'', http://www.britannica.com Comment: andradite [Accessed May 20, 2003]. | * ''Encyclopedia Britannica'', http://www.britannica.com Comment: andradite [Accessed May 20, 2003]. | ||
| − | |||
* C.W.Chesterman, K.E.Lowe, ''Audubon Society Field Guide to North American Rocks and Minerals'', Alfred A. Knopf, New York, 1979 | * C.W.Chesterman, K.E.Lowe, ''Audubon Society Field Guide to North American Rocks and Minerals'', Alfred A. Knopf, New York, 1979 | ||
Revision as of 13:24, 20 December 2022
Description
A type of Garnet composed of a calcium iron silicate. The color of andradite may be yellow, red, green, brown or black. Bright green andradite, or demantoid, is also called the emerald of the Urals. Gemstone quality andradite is mined in the Ural Mountains, Italy, Switzerland, Norway, France, and in the United States (Arkansas and New Jersey).
Synonyms and Related Terms
garnet; demantoid (green, emerald of the Urals); topazolite (yellow); melanite (brown or black); andradita (Esp.); andradite (Port.); Andradit (Deut.); andradiet (Ned.)
Physical and Chemical Properties
- Fracture = conchoidal
- Luster = vitreous to resinous
- Streak = colorless
- Dispersion = 0.057
- Fluorescence = inert
- Pleochroism = none
- Birefringence = none
| Composition | Ca3Fe2Si3O12 |
|---|---|
| Mohs Hardness | 6.5 - 7.0 |
| Density | 3.9 g/ml |
| Refractive Index | 1.887 |
Comparisons
Resources and Citations
- Mineralogy Database: Andradite
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971
- Encyclopedia Britannica, http://www.britannica.com Comment: andradite [Accessed May 20, 2003].
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979