Sunday, April 22, 2012

  
  

Tuesday, May 09, 2006

Bloodstone: the Martyr's Gem


Bloodstone, green jasper dotted with bright red spots of iron oxide, was treasured in ancient times and long served 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 reflected in the ocean.

Medieval Christians often used bloodstone to carve scenes of the crucifixion and martyrs, leading it to also be dubbed martyr's stone. The legend of the origin of bloodstone says that it was first formed when some 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 museum in Paris.

Even today, finely powdered bloodstone is used as a medicine and aphrodisiac in India. Perhaps that explains why today it is difficult to find fine specimens of bloodstone on the market. Bloodstone is mined in India, Australia, and the United States.

Chalcedony is one of the cryptocrystalline varieties of the mineral quartz, having a waxy luster. Chalcedony may be semitransparent or translucent and is usually white to gray, grayish-blue or some shade of brown, sometimes nearly black. Other shades have been given different names. A clear red chalcedony is known as carnelian or sard; a green variety colored by nickel oxide is called chrysoprase. Prase is a dull green and onyx is black and white banded. Plasma is a bright to emerald-green chalcedony that is sometimes found with small spots of jasper resembling blood drops; it has been referred to as blood stone or heliotrope. Flint is also a variety of chalcedony.

People living along the Central Asian trade routes used various forms of chalcedony, including carnelian, to carve intaglios, ring bezels (the upper faceted portion of a gem projecting from the ring setting), and beads that show strong Graeco-Roman influence. Fine examples of first century objects made from chalcedony, possibly Kushan, were found in recent years at Tillya-tepe in north-western Afghanistan. Hot wax would not stick to it so it was often used to make seal impressions.

The term chalcedony is derived from the name of the ancient Greek town Chalkedon in Asia Minor, in modern English usually spelled

 
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