Our Gems

Opal

History and Folklore

Originally it was believed that Romans established opals as a gemstone and its name came from opalus. Now, however, it is believed to come from the Sanskrit word upala meaning "valuable stone". Through most of history, opals have been regarded as precious stones and were believed to carry good luck. During the 18th and 19th centuries, opals acquired a bad reputation. In a novel by Sir Walter Scott (Anne of Geierstein - 1829) a Baroness dies after a drop of holy water falls on her opal and it becomes colorless. Despite superstitions, the opal still found its place in French Crown Jewels, Holy Roman Emperor's
crown and much of Queen Victoria's jewelry.

Facts and Information

Opal is one of the most intriguing gemstones because of its many unique plays of color. Opal is a form of silica that contains 6-10% water. The "play of color" comes from light reflecting from the very tiny silica spheres. Although over 90% of opals come from Australia, some do come from Brazil and Mexico. Recently, opals have also been found in Africa.

There are several types of opal:

  • White Opal - An opal that has a base white color with a play of other colors.
  • Crystal Opal - Transparent to semi-transparent body with strong play of colors.
  • Black and Grey Opal - Opal that has black, dark blue, dark grey and dark green body with a play of color. Almost all black opals come from Australia, and Lightning Ridge produces most of the finest gems.
  • Boulder Opal - Opal with dark base and color occurring in matrix rock.
  • Jelly Opal - Transparent to semi-transparent opal with little play of color.
  • Fire Opal - Opal that is transparent to semi-transparent with red, yellow or orange to brown body color. This can be with or without play of color. Also referred to as Mexican Opal.

Besides the solid opals listed above, there are also opal doublets, a layer of opal glued to a backing - and also opal triplets, a cap with opal in the center and a backing all glued together.

Gemstone Identification and Characteristics

  • R.I.: 1.45 (+.02, -.08)
  • Hardness: 5 - 6.5
  • S.G.: 2.15 (+.08, -.90)

Cleaning Methods

  • Never use in ultrasonic
  • Safe in warm, soapy water
  • Never use in steamer

Major Sources

  • Brazil
  • Australia
  • Mexico