Key facts
- Category
- Tectosilicate minerals
- Group
- Quartz group
- Formula
- Si O 2 ( silicon dioxide )
- Ima status
- Variety of chalcedony
- Crystal system
- Trigonal ( quartz ), monoclinic ( moganite )
- Color
- Dark shades of green , often with red or yellow spots; sometimes mixed with whitish silica
- Fracture
- Conchoidal
- Mohs scale hardness
- 6.5–7
- Luster
- Vitreous
- Diaphaneity
- Opaque to translucent
- Refractive index
- 1.53–1.54
via Wikipedia infobox
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Encyclopedic overview
Heliotrope (from Ancient Greek ἥλιος (hḗlios) 'sun' and τρέπειν (trépein) 'to turn') (also called ematille, Indian bloodstone or simply bloodstone), is a mineral aggregate, a cryptocrystalline mixture of quartz that occurs mostly as jasper (opaque) or sometimes as chalcedony (translucent).
The "classic" bloodstone is translucent to opaque green chalcedony and red jasper that contains inclusions of hematite. The red jasper may resemble spots of blood, hence the name bloodstone. Other colors of chalcedony may also occur in Indian bloodstone, such as white, yellow, or blue.
Excerpted from Wikipedia’s “heliotrope” article, available under the CC BY-SA 4.0 licence.