Chlorastrolite
Chlorastrolite is named from Greek "chloros" - green, and "astros" - star.
Chlorastrolite is often mottled light and dark green. The most desirable pattern resembles tortoiseshell. It is widely used in jewelry items that are not subjected to heavy wear.
Chlorastrolite is the state stone of Michigan, USA.
Chlorastrolite is often mottled light and dark green. The most desirable pattern resembles tortoiseshell. It is widely used in jewelry items that are not subjected to heavy wear.
Chlorastrolite is the state stone of Michigan, USA.
| General Information | ||||||||||||||||||||||||||||||
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| A variety or type of: | Pumpellyite Subgroup | |||||||||||||||||||||||||||||
| Chemical Formula |
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| Physical Properties of Chlorastrolite | ||||||||||||||||||||||||||||||
| Mohs Hardness | 5 to 6, Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Specific Gravity | 3.1 to 3.5, Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Cleavage Quality | None, Gemstones (2009) | |||||||||||||||||||||||||||||
| Fracture | Splintery, Gemstones (2009) Granular | |||||||||||||||||||||||||||||
| Optical Properties of Chlorastrolite | ||||||||||||||||||||||||||||||
| Refractive Index | 1.7, Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Birefringence | 0.010, Gemstones (2009) | |||||||||||||||||||||||||||||
| Pleochroism | Nil, Gemstones (2009) | |||||||||||||||||||||||||||||
| Dispersion | Nil, Gemstones (2009) | |||||||||||||||||||||||||||||
| Colour | ||||||||||||||||||||||||||||||
| Colour (General) | Green and white patterns. The most desirable pattern resembles tortoiseshell., Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Causes of Colour | Green, Fe2+-O-Fe3+ charge transfer coordination, plus Fe2+, Pragmatic Spectroscopy For Gemologists (2011) | |||||||||||||||||||||||||||||
| Transparency | Opaque, Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Lustre | Silky,Pearly, Gemstones (2009) | |||||||||||||||||||||||||||||
| Crystallography of Chlorastrolite | ||||||||||||||||||||||||||||||
| Crystal System | Orthorhombic, Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Habit | Fibrous aggregates, Gems, Sixth Edition (2006) More from other references | |||||||||||||||||||||||||||||
| Geological Environment | ||||||||||||||||||||||||||||||
| Where found: | Occurs in cavities in amygdaloidal basalt tending to fill the smaller voids, few of which are larger than a pea., Gemstones (2009) | |||||||||||||||||||||||||||||
| Further Information | ||||||||||||||||||||||||||||||
| Mineral information: | Chlorastrolite information at mindat.org | |||||||||||||||||||||||||||||
| Significant Gem Localities | ||||||||||||||||||||||||||||||