Bloodstone

Bloodstone, also called heliotrope, is a dark green variety of chalcedony (or jasper) marked by vivid red or orange spots caused by iron oxide. The classic combination of deep green with blood-red flecks gives the stone its dramatic name and long history of symbolism.

It has been used since ancient times for seals, amulets, and carvings, and was especially associated in medieval Christianity with the blood of Christ. The name heliotrope comes from old beliefs that the stone could turn the sun red when placed in water.

It remains a popular men's gemstone and the traditional birthstone for March.

Bloodstone forms like other chalcedony, from silica-rich solutions depositing microcrystalline quartz in cavities and fractures of volcanic and sedimentary rocks. The green base color comes from included chlorite or amphibole minerals.

The characteristic red spots are concentrations of iron oxide (hematite) scattered through the green silica. Variations in the amount and distribution of these minerals produce the spotted or streaked appearance.

The finest traditional bloodstone comes from India, with additional sources in Brazil, Australia, China, and the United States.

Look for an opaque to slightly translucent dark green stone with distinct red or orange spots and flecks. The green base with red dots is highly diagnostic.

Bloodstone has a hardness of 6.5-7, a waxy to dull luster, and a white streak; it scratches glass and resists a knife. The red marks are part of the stone, not surface staining.

Look-alikes include green jasper without red spots, and dyed stones imitating the pattern. Plasma is a related green chalcedony lacking the red spots. Heliotrope proper always shows the red inclusions.

Bloodstone is cut into cabochons, signet rings, beads, and carvings, and is a popular choice for men's jewelry. It is the traditional birthstone for March alongside aquamarine.

Historically it was carved into amulets and seals and credited with the power to stop bleeding and grant courage. Metaphysically it is associated with vitality, strength, and grounding, though these are folk and spiritual beliefs.

Value depends on a deep, even green base, well-distributed bright red spots, and good polish without cracks.