Bloodstone (also known as heliotrope) are opaque, green, spotted varieties of chalcedony, used for decorative carvings and cameos. The dark green of bloodstone is spotted with red, because of the presence of iron oxides. These distinctive spots appear to resemble blood, and provide the stone its name.
India is the primary source of bloodstone, but it also occurs in Brazil, China, Australia and the United States.
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 known as bloodstone, so this variety is known as bluestone.