Heliotrope (bloodstone)
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Heliotrope, is a mineral aggregate, a cryptocrystalline mixture of quartz that occurs mostly as jasper or sometimes as chalcedony.
A tumble-polished pebble of heliotrope, also called bloodstone
A rough specimen of bloodstone
Hematite
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Hematite, also spelled as haematite, is a common iron oxide compound with the formula Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is
Heliotrope (bloodstone)
…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…
Hematite crystals from Brazil
Crystal structure of hematite
Image mosaic from the Mars Exploration Rover Microscopic Imager shows hematite spherules partly embedded in rock at the Opportunity landing site. Image is around 5 cm (2 in) across.
A rare pseudo-scalenohedral crystal habit