What physical properties do opals possess? Where do these gemstones come from?

Opals range fin color from clear to white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, reds and black are considered to be extremely rare, whereas white and greens are considered to be commonplace. Since opals are considered a soft gemstone, they are usually inlaid in jewelry to keep them from being damaged. Opals are the October birthstone and are very popular in birthstone jewelry.

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Opal is a form of silica (SiO2), which contains water inside the mineral structure. Its hardness level is 5.5-6.5 and the specific gravity level is 2-21/4.

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Opal is a multicolored gemstone with extremely high water weight ranging from 3 - 20%. For many centuries opal has been incorporated in jewelry and carvings. The main sources of opal are Australia, Europe (Czechoslovakia), Mexico and the United States (Nevada and Idaho). In fact opal is the national gemstone of Australia. Opal belongs to the silica family of gemstones.


Opal is the birthstone for the astrological sign of Libra as well as the traditional 14th and 18th wedding anniversary gemstone. In fact, opal jewelry has been presented as a romantic gift since Napolean presented Josephine with a stunning opal gemstone.


Spiritually, opals are said to have the power to boost emotions and assist in bringing out feelings. Depending on the period, opals have been believed to possess curing powers for eye diseases, blood disorders, depression, reproduction. Black opals are considered lucky gemstones, protecting the wearer from the evil eye.

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As with any gemstone, the basis for the estimation of an opal's worth includes the following: clarity, size, polish, and rarity. Generally speaking, jewelers only seldom know the true value of any gemstone. The people that are most familiar with all the intricate aspects of gemstone evaluation are appraisers, preferably GIA certified appraisers. Regarding opals, the prices may range from just a few dollars a carat to several thousand dollars per carat. These gemstones can actually cost more per carat than a flawless diamond at level D. Opals may also come in different colors – they can be black, white or crystal. The black opals are the most costly gemstones because they are especially rare and beautiful. The value of an opal is not determined in any cut and dry method. At times, professionals will also provide slightly different appraisals because they may prefer a certain pattern or color. The problem with determining an opal's value is that each gemstone has its own special qualities. Usually opals are ranked on a scale of 1 – 5 (1 is of the lowest quality, 2 is commercial level, 5 is brilliant). The market for high quality opals in the US is not particularly good since most of the population is simply not aware of the value of an opal gemstone.

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