Hydrogrossular
Tasmania, Australia
21.30 carats
© Giovanni Scapin 2015
Colours vary from green to bluish green, sometimes pink, white or grey, translucent to opaque. The stones may have black spots or blotches.
Green varieties are often used as jade alternatives. It is also known as "Transvaal jade" or "African jade".
| General Information | ||||||||||||||||||||||
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| A variety or type of: | Grossular, which is a variety of Garnet Group | |||||||||||||||||||||
| Chemical Formula |
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| Physical Properties of Hydrogrossular | ||||||||||||||||||||||
| Mohs Hardness | 7.5 to 8, Gemmological Tables (2004) | |||||||||||||||||||||
| Specific Gravity | 3.25 to 3.40, Gemmological Tables (2004) | |||||||||||||||||||||
| Optical Properties of Hydrogrossular | ||||||||||||||||||||||
| Refractive Index | 1.680 to 1.712, Gemmological Tables (2004) Rose-redMore from other references | |||||||||||||||||||||
| Optical Character | Isotropic, Gemmological Tables (2004) | |||||||||||||||||||||
| Colour | ||||||||||||||||||||||
| Colour (General) | Rose-red, green, Gemmological Tables (2004) | |||||||||||||||||||||
| Causes of Colour | Green ("Transvaal jade"), Cr3+ in octahedral coordination. Pink, Mn3+ in octahedral coordination, Pragmatic Spectroscopy For Gemologists (2011) | |||||||||||||||||||||
| Transparency | Translucent,Opaque, Gemmological Tables (2004) | |||||||||||||||||||||
| Crystallography of Hydrogrossular | ||||||||||||||||||||||
| Crystal System | Isometric, Gemmological Tables (2004) | |||||||||||||||||||||
| Further Information | ||||||||||||||||||||||
| Mineral information: | Hydrogrossular information at mindat.org | |||||||||||||||||||||