A heliotrope, also known as a bloodstone.
|SiO2 (silicon dioxide)|
|Color||Green with red or yellow spots|
|Mohs scale hardness||6.5–7|
The mineral aggregate heliotrope, also known as bloodstone, is a variety of jasper or chalcedony (which is a cryptocrystalline mixture of quartz). The "classic" bloodstone is green jasper (chalcedony) with red inclusions of hematite.
The red inclusions are supposed to resemble spots of blood; hence the name "bloodstone". The name "heliotrope" (from Greek ἥλιος helios, Sun, τρέπειν trepein, to turn) derives from various ancient notions about the manner in which the mineral reflects light. These are described, e.g., by Pliny the Elder (Nat. Hist. 37.165). 
Heliotrope is sometimes used in carved signet rings and is the traditional birthstone for March.
The primary source of the stone is India. It is also found in Armenia, Azerbaijan, Brazil, Bulgaria, China, Australia, and the United States. There is also an outcrop of bloodstone on the Isle of Rum, in Scotland.
- Hall, Candy A. (1994). Gem Stones. DK Publishing. ISBN 1-56458-498-4.
- "heliotrope". Merriam-Webster Dictionary. m-w.com.
- Media related to Heliotrop at Wikimedia Commons