October Birthstones

Opal’s kaleidoscopic play-of-color can suit many changing moods and tastes, making this gemstone appropriate for anyone. It is also the traditional gift to celebrate 14th wedding anniversaries.

Like diamonds, opals can be evaluated by color, clarity, cut, and carat weight. But these unique gemstones also have several additional conditions to consider. Keep reading to know what to look for when buying opal jewelry.

Opal Color

One of the first conditions to look at when you go to buy opal jewelry is the color. Opals can display a myriad of hues, from fiery reds and oranges to serene blues and greens.

In fact, color is the key factor of opal quality: both the background “body color” and the flashing “play-of-color.” Dark backgrounds provide more contrast against vivid play-of-color, making black opal more highly valued than milky white varieties.

Warm colors like red and orange are generally rarer and more valuable than common blues and greens, although color range and coverage also play a role. The most prized opals have vibrant and saturated colors that are easily visible across the stone.

Patterns of Opal

Pattern is another factor unique to opal. This refers to the arrangement and play of the gemstone’s internal colors.

Descriptive names like “stained glass,” “peacock,” “rolling fire,” and “Chinese writing” distinguish opal patterns. Gemologists typically prefer large, concentrated patches—referred to as “harlequin”—over small specks.

The uniqueness and distinctness of the gemstone’s pattern can significantly influence the value of opal jewelry. The more unique and vibrant the pattern, the more valuable the opal is likely to be.

Opal Clarity

Clarity in opals doesn’t function the same way as in transparent gemstones like diamonds. Instead, clarity in opal relates to the stone’s transparency and any inclusions or imperfections.

Different opal varieties have varying clarity standards. Crystal opals should be transparent, while opacity makes black opals more valuable. A cloudy, milky haze alludes to minute inclusions and instability, while lowering any opal’s value. Any significant inclusions that disrupt the play-of-color can decrease the stone’s value.

Due to high water content, opal can easily crack or “craze” under extreme temperatures, dehydration, or direct light. Crazed opal sells at much lower prices and is more susceptible to fracture. Even high-quality opal demands delicate care to preserve its unique beauty.

Cut

The cut of an opal is all about showcasing its best features. Unlike many other gemstones, opals aren’t always cut in standard shapes or proportions. Instead, they’re often cut to highlight their unique play-of-color and pattern. A well-cut opal will maximize its brilliance and display its colors from various angles.

Fine opals are often cut into irregular shapes to emphasize play-of-color. When possible, opals should be cut cabochon with rounded domes.

But most opal comes in thin layers, which are commonly mounted on another dark stone like onyx or obsidian (as a doublet) and sometimes capped with clear glass or plastic (as a triplet) to make this fragile gemstone more wearable.

Caring for Opal Jewelry

Opals are relatively soft gemstones, with a hardness of around 5.5-6.5 on the Mohs scale. This makes them susceptible to scratches and abrasions. To care for your opal jewelry, avoid wearing it during activities where it could get knocked or scratched.

Opal gems and jewelry should be stored in a place where they aren’t exposed to high temperatures, direct sunlight, or low humidity in order to avoid dehydration and crazing. Place them in a padded cloth bag to avoid being scratched by other jewelry. For longer storage periods, place your opal in cotton wool with a few drops of water.

Opal gemstones may be treated with wax, oil, smoke, plastic, or other additives to enhance luster. Identifying enhancements or synthetic materials may require specialized lab equipment, so it’s best to work with an American Gem Society jeweler who understands the criteria that determine the value of opal jewelry.

Where to Buy Opal Jewelry

Feeling more confident buying opal jewelry? Looking for the best place to buy opal jewelry?

Find a jeweler near you to help pick out the right opal for your preferences.