Astrophyllite
Russia
3.13 carats
© raregemhunter
Astrophyllite is usually opaque to translucent, but may be transparent, brown to golden-yellow colour.
Astrophyllite is often cut into slabs and polished. It is sometimes used in jewelry where it is fashioned into cabochons.
Astrophyllite Gemstones by Colour
This table shows the variety of hues this gemstone can be found in. Click on a photo for more information.
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| General Information | ||||||||||||||||||||||||||||||
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| Chemical Formula |
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| Physical Properties of Astrophyllite | ||||||||||||||||||||||||||||||
| Mohs Hardness | 3, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Specific Gravity | 3.2 to 3.4, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Tenacity | Brittle, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Cleavage Quality | Perfect,Poor, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Optical Properties of Astrophyllite | ||||||||||||||||||||||||||||||
| Refractive Index | 1.678 to 1.758, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Optical Character | Biaxial/+, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Pleochroism | Strong: deep orange-red - orange-yellow - lemon-yellow, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Dispersion | Strong, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Colour | ||||||||||||||||||||||||||||||
| Colour (General) | Bronze-yellow to gold-yellow, brown to reddish brown, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Transparency | Translucent,Opaque, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Lustre | Pearly,Greasy,Submetallic, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Crystallography of Astrophyllite | ||||||||||||||||||||||||||||||
| Crystal System | Triclinic, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Habit | Crystals tabular, bladed or acicular, some faces commonly striated, to 10 cm; groups may be stellate, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Geological Environment | ||||||||||||||||||||||||||||||
| Where found: | In nepheline syenites, alkali granites, and their pegmatites; less commonly in fenites and other metasomatized rocks; in nepheline syenite gneisses and paragneisses, Handbook of mineralogy (2001) | |||||||||||||||||||||||||||||
| Further Information | ||||||||||||||||||||||||||||||
| Mineral information: | Astrophyllite information at mindat.org | |||||||||||||||||||||||||||||