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OPAL

    When comparing opal prices, find out what type of opal you’re looking at. Here are the various types:

COMMON OPAL and POTCH : Opal with no play-of-color (shifting of spectral colors) and a translucent to opaque transparency. Opal with a play-of-color, the most popular kind, is called precious opal by many opal dealers.

LIGHT OPAL : Opal with a play-of-color and a light body color. White Opal is the most common type. It typically has an off-white background color and can be translucent to opaque. Milky white stones with little play-of-color are used in budget-priced jewelry. White opals with a brilliant play-of-color can retail for a few hundred dollars per carat. When an opal has a high transparency, a near colorless body color and a distinct play-of-color, then it’s called a crystal opal. This is the most valued light opal. In its highest qualities it can cost more than $2500 per carat retail.

BOULDER OPAL : Opal that is still attached to the rock (Usually ironstone) in which it is found. Boulder opal, which can resemble either light or dark opal, is typically cut in irregular shapes. Gem quality boulder opal may sell for $5,000 to $50.000 per piece, but you can get attractive stones for a few hundred dollars. Boulder opal is mined in Queensland, Australia.

BLACK (DARK) OPAL : A generic term for any opal with a play-of-color against a dark background. If the stone is transparent to semi-transparent and dark with a play-of-color, the stone is a black crystal opal. Today top-grade black opal can sell for as much as $15,000 a carat. It’s found in Lightning Ridge, Australia.

MATRIX OPAL or OPAL-IN-MATRIX : Stones with lines or spots of opal randomly scattered through the matrix (The rock in which a mineral, fossil or pebble is found). The most common type is a porous opal from Andamooka, Australia, which is often dyed black to simulate black opal. Yowah opal, another type of matrix opal, is completely natural and is mined in Yowah, South Queensland. Matrix opal normally sells for much less than boulder opal.

FIRE OPAL : A transparent to translucent opal with a red orange, yellow or brownish body color both with or without a play-of-color. Mexico is the principal source. The most valued fire opal is reddish orange, transparent, and has a play-of-color within the stone. This quality can retail for as much as $300 per carat. Low quality brownish stones may sell for $5 per carat.

Care tips : Since opals are relatively soft and fragile, they require special care. Avoid heat and sudden changes of temperature, Do not wear them while sunbathing or set them on a sunny window still or under hot lights. Don’t clean them in ultrasonics. Instead, wash them in water with a mild soap and soft cloth. (Opal doublets and triplets, however, should not be immersed in water)