Heliotrope (mineral)

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Heliotrope
Quarz - Heliotrop (Blutjaspis).JPG
A heliotrope, also known as a bloodstone.
General
Category Mineral
Formula
(repeating unit)
SiO2 (silicon dioxide)
Identification
Color Green with red or yellow spots
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 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). [1]

Heliotrope features in one of Boccaccio's stories in the Decameron.

Heliotrope is sometimes used in carved signet rings and is the traditional birthstone for March.

Sources[edit]

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.

References[edit]

  1. ^ "heliotrope". Merriam-Webster Dictionary. m-w.com. 

External links[edit]

  • Media related to Heliotrop at Wikimedia Commons