Difference between revisions of "Andradite"
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A type of [[garnet|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). | A type of [[garnet|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). | ||
| + | [[[SliderGallery rightalign|Andradite Infrared RRUFF R040001.png~IR-ATR (RRUFF)|Andradite Raman RRUFF R040001.png~Raman (RRUFF)|Andraditeitaly1.jpg~Raman (U of Parma)]]] | ||
== Synonyms and Related Terms == | == Synonyms and Related Terms == | ||
| Line 7: | Line 8: | ||
garnet; demantoid (green, emerald of the Urals); topazolite (yellow); melanite (brown or black); andradita (Esp.); andradite (Port.); Andradit (Deut.); andradiet (Ned.) | 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 == | |
| − | + | * Cubic crystal system with dodecahedra/trapezohedra combinations or granular to massive crystals | |
| − | == | + | * Cleavage = none |
| − | + | * Fracture = conchoidal to uneven | |
| − | Fracture = conchoidal | + | * Luster = vitreous to resinous |
| + | * Streak = colorless to white | ||
| + | * Dispersion = 0.057 | ||
| + | * Fluorescence = inert | ||
| + | * Pleochroism = none | ||
| + | * Birefringence = none | ||
{| class="wikitable" | {| class="wikitable" | ||
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|- | |- | ||
! scope="row"| Density | ! scope="row"| Density | ||
| − | | 3.9 | + | | 3.8 - 3.9 g/ml |
|- | |- | ||
! scope="row"| Refractive Index | ! scope="row"| Refractive Index | ||
| 1.887 | | 1.887 | ||
|} | |} | ||
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| − | |||
| − | |||
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== Comparisons == | == Comparisons == | ||
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[[media:download_file_398.pdf|Properties of Gemstones]] | [[media:download_file_398.pdf|Properties of Gemstones]] | ||
| + | ==Resources and Citations== | ||
| − | + | * Mineralogy Database: [http://www.webmineral.com/data/Andradite.shtml Andradite] | |
| − | + | * Gem Identification Lab Manual, Gemological Institute of America, 2016. | |
| − | + | * Wikipedia: [https://en.wikipedia.org/wiki/Andradite Andradite] (Accessed Dec 2022) | |
* 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 | ||
| − | |||
* 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 | ||
Latest revision as of 11:47, 23 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
- Cubic crystal system with dodecahedra/trapezohedra combinations or granular to massive crystals
- Cleavage = none
- Fracture = conchoidal to uneven
- Luster = vitreous to resinous
- Streak = colorless to white
- Dispersion = 0.057
- Fluorescence = inert
- Pleochroism = none
- Birefringence = none
| Composition | Ca3Fe2Si3O12 |
|---|---|
| Mohs Hardness | 6.5 - 7.0 |
| Density | 3.8 - 3.9 g/ml |
| Refractive Index | 1.887 |
Comparisons
Resources and Citations
- Mineralogy Database: Andradite
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Wikipedia: Andradite (Accessed Dec 2022)
- 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