Bloodstone (also called heliotrope) and plasma are both opaque, Green, spoiled Varieties of chalcedony, used lord decorative carvings and cameos. The Dark green of bloodstone is spoiled with red, due to he presence of iron oxides. These distinctive spots seem to resemble blood, and give the stone its name. Plasma is also green and may have yellowish sports.

India is the primary source of bloodstone, but it also occurs in Brazil, China, Australia, and the USA. Plasma is mined in Zimbabwe.

In the middle Ages, bloodstone was attributed with special powers, as the spots were thought to be the blood of Jesus Christ. In (Germany, hematite is also called bloodstone, so this variety is known as Milestone.