Double Refraction: None
A member of the chalcedony family of quartz, Jasper gets its name from the Greek word for spotted stone. Jasper consists of a micro-crystalline aggregate, but jasper will always contain impurities. These impurities, often clay, iron, calcite, and hematite, will sometimes reach 20% of the total composition of the stone. Because of the impurities found in jasper, a stone of a single color is rare to come by. Stones are more often streaked, banded, or spotted. Depending on composition, jaspers are usually red, but can be yellow, brown and green. Very rarely, jasper will be blue or black. Grey varieties of jasper are often called hornstone.
Too abundant to be very expensive, jasper is often made into cabochons, ornamental objects, stone mosaics, bowls and other objects. The Saint Wenceslas Chaple in Prague is adorned with jasper as well. Also, much fossilized wood has been "petrified" with jasper.
Jasper is found all over the world, from Dekken, in India, to the Ural Mountains in Russia, France and several states in the USA, namely Utah, Arizona, California, Wyoming, Idaho. There is also a Jasper National Park in the Canadian Rockies. It is located in the province of Alberta, along its border with British Columbia. The park is a nature reserve, and it is not known if the gem is found in abundance there.
Cardano, an ancient greek, believed the stone would give the wearer extra strength, allowing him to be victorious in battle. Greek physicians believed amulets of jasper to cure colic. These amulets all had an engraving of Hercules as he defeated the Nemean Lion. This continued for several years and amulets of Jasper, both green and red, were used several centuries later as cures for stomach problems and hemorrhages
Precious Stones, by Dr. Max Bauer. Charles E. Tuttle Company: Rutland Vermont and Tokyo, Japan, 1969
Gemstones of the World, by Walter Schumann. Sterling Publishing Co., New York, 1979
Simon and Schuster's guide to Rocks and Minerals, Simon and Schuster Inc. New York, 1978
The Magic of Jewels and Charms, Dr. George Frederick Kunz. J.B. Lippincott company, Philadelphia and London, 1915