Heliotrope (mineral)
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| Heliotrope | |
|---|---|
.JPG) A heliotrope, also known as a bloodstone. |
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| General | |
| Category | Mineral |
| Chemical formula | SiO2 (silicon dioxide) |
| Identification | |
| Crystal system | Trigonal |
| Mohs scale hardness | 6.5-7 |
| Luster | Vitreous |
| Specific gravity | 2.61 |
| Refractive index | 1.53-1.54 |
| Birefringence | 0.004 |
The mineral heliotrope, also known as bloodstone, is a form of chalcedony (which is a cryptocrystalline mixture of quartz and its monoclinic polymorph moganite). The "classic" bloodstone is green chalcedony with red inclusions of iron oxide or red jasper. Sometimes the inclusions are yellow, in which case the mineral is given the name plasma.
The red inclusions are supposed to resemble spots of blood; hence the name "bloodstone". The name "heliotrope" (from Greek helios, Sun, trepein, to turn) derives from various ancient notions about the manner in which the mineral reflects light.
[edit] Sources
The primary source of the stone is India. It is also found in Brazil, China, Australia and the United States. There is also an outcrop of Bloodstone on the Isle Of Rum, one of the Small Isles in Scotland.
[edit] Legends and lore
Bloodstone is the original birthstone for March. Today, bloodstone, jasper and aquamarine are all considered the gemstones for March.[citation needed]
[edit] References
Hall, Candy A. (1994). Gem Stones. DK Publishing. ISBN 1-56458-498-4
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