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Summary Article: Jasper
From Guide to Gems

Jasper is a massive opaque variety that is a mixture of chalcedony, quartz and opal. The name comes from the Latin name for the stone, iaspis, which probably also referred to other types of chalcedony. Jasper is found as small veins and replacements in different metamorphic and sedimentary rocks and in cracks of volcanic rocks. It is fine-grained and coloured by red and yellow iron oxides or green chlorite and actinolite. It often shows a combination of red, yellow, brown, green, and grey-blue. Orbicular jasper is a red variety containing white or grey patterns shaped like eyes. Riband jasper is striped, while hornstone is grey.

Jasper was used by the ancient Egyptians, Greeks, and Romans who carved portraits and such ornamental objects as amulets. It was believed that a person wearing jasper would be protected from illness, especially stomach problems. It has traditionally been used as a gemstone for jewellery such as brooches, earrings, necklaces, pendants, intaglios, and cameos, as well as for carvings and mosaics. It is normally cut as cabochons. Boulders of jasper weighing several hundred kilogrammes (pounds) have been sculpted in Ukraine and the Urals of Russia.

Jasper occurs thoroughout the world. Various colours are found in the USA, such as orbicular jasper in California and jasperized fossil wood in Arizona. The Urals of Russia yield red, brown, green, and white riband jasper. Kazakhstan has a red-and-green variety, while Venezuela and India have red jasper. It also occurs in the Libyan desert, the Nile valley of Egypt, and the Rhineland of Germany.

Cabochon-cut jasper gem

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