Bloodstone

Bloodstone, also called heliotrope, is a variety of chalcedony, the microcrystalline form of quartz (SiO₂), dark green and flecked with red jasper. Bloodstone (also called heliotrope) is a dark green chalcedony speckled with spots of bright red jasper. The green base color comes from chlorite and hornblende mineral inclusions dispersed throughout the microcrystalline quartz. The red spots are iron oxide (hematite) concentrations.

It forms through the same process as other chalcedony varieties - silica-rich fluids depositing microcrystalline quartz in cavities and fractures within host rock. The iron oxide spots form when iron-bearing solutions penetrate the chalcedony along micro-fractures or in localized pockets during or after the primary formation.

A related variety called plasma is similar but has yellow spots instead of red (from goethite rather than hematite). The distinction between bloodstone and plasma is primarily the color of the inclusions.

Bloodstone is identified by its dark green color with red to orange spots - this specific combination is unique among common gemstones. At hardness 7, it's durable and takes a good polish. The waxy luster and opaque character are typical of chalcedony varieties.

Distinguish from green jasper (may have red spots but is typically lighter green), moss agate (green inclusions are filamentous, not spotted), and ruby in zoisite (pink-red and green, different minerals). The red spots in genuine bloodstone are irregularly distributed and vary in size.