The martyr's gem
Bloodstone, green jasper dotted with bright red spots of iron oxide, was treasured in ancient times and served for a long time as the birthstone for March. This attractive chalcedony quartz is also known as heliotrope because in ancient times polished stones were described as reflecting the sun: perhaps the appearance of the gem reminded the ancients of the red setting sun, mirrored in the ocean.
Medieval Christians often used bloodstone to carve scenes of the crucifixion and martyrs, for which reason it was also dubbed the martyr's stone. According to the legend about the origin of bloodstone, it was first formed when drops of Christ's blood fell and stained some jasper at the foot of the cross.
A beautiful example of carved bloodstone with the seal of the German Emperor Rudolf II can be seen at the Louvre in Paris.
Even today, finely pulverised bloodstone is used as a medicine and aphrodisiac in India. Perhaps that explains why it is now rather difficult to find fine specimens of bloodstone on the market.
Bloodstone is mined in India, Australia, and the United States.