Australian Natural Adventures
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How to choose an opal
First, decide how much you are willing to pay, and what you want to do with your opal. The combination of these two may determine the type of opal you choose. If you want a ring, or a brooch, you may want a larger opal than for earrings or a petite drop pendant. In this case a doublet or triplet will get you a larger and flashier opal than a solid opal. If you buy your jewelry with investment in mind, then buy a solid opal. Small gifts for friends, children etc are easily served with triplets. It may even depend on what you wear with your opal. A light, milky opal necklace may lay nicely on a black evening dress, similar to pearls, and black or boulder opal on a more colorful outfit.
As far as selecting the actual opal itself, look for what appeals to you. If intrinsic value is not important, then just choose the size, color and shape that you like. It's your choice, and your opal. There's no "better" type, or color, as far as personal preference goes. Some people prefer large areas of single color, others prefer a mix of colors always showing. Some like the natural look of opals with inclusive flaws, such a tiny veins (although these lower intrinsic value).
most common color pattern is sometimes called the floral
pattern, where the colors are spread through the face, more or less
Rarer, and therefore more valuable, patterns include the wonderful
The straw pattern, where the color appears as lines, is more linear in appearance.
writing, with larger and shorter single color lines against
a dark background is very rare.
Harlequin, a checkerboard pattern, may be the rarest of all.
If intrinsic value is important, there are some guidelines to follow. Remember, opal is very subjective, and so there are no hard and fast rules as there are with other gems. Determining the value of an emerald-cut white diamond, for example, is simple - weight, clarity, and flaws will add up to an objective value. Not so with opal. If there is one over-riding factor, however, it is brilliance. Brilliant stones of any color will be more valuable than duller stones of the rarer colors, with few exceptions. Red is the rarest color in opals, and so the amount of red will increase value. But again, a brilliant, blue-green opal with particular depth and flash of color, especially with an attractive pattern, will be more valuable than a less intense and less attractively patterned opal with more red/orange. The more of the stone that is colored, the more valuable the opal, regardless of type. The pattern will influence value, but as the vast majority of opals are floral patterned, this is not usually as significant as brilliance and color. However, opals with larger areas of solid color are usually more valuable than those with smaller areas.
In a very general way, all other things being equal, black opal is more valuable than either boulder or light opal, in that order. But again, what is important is the individual stone.
Generally, regular shapes are more valuable than irregular shapes, in part as they are more easily set into jewelry. An exception is boulder opal; this is often set in more irregular pieces. Many opals will have some groundstone on the back of the stone; boulder opal has a slice of groundstone. Such inclusions won't decrease the value of the opal, but noticeable inclusions, cracks or other marks on the face will.
Where to buy opal
Opals are most easily bought at stores in the major cities, especially in areas visited by tourists. Such dedicated stores have a wide selection, and usually expert advice on hand. Some are larger, such as the National Opal Collection store in Sydney has an adjunct of the Australian Museum on site with extensive information and displays about opals. It's worth a visit even if you're not im the market, or are going to buy elsewhere. Our preferred store, which also come highly recommended by our clients, is Altmann & Cherney, in both Melbourne and Sydney. The owners and staff are very experienced, and control the process - they cut, polish and manufacture their own opal, diamond and pearl jewelry, and is family owned from its beginning in 1948. If you are visiting an opal field, there are local shops representing miners at the field; mostly these will have a smaller selection and just carry the sort of opal found locally. The city stores and many of the field stores will carry both set and unset stones; some field stores will only carry unset stones. Lastly, some prefer to buy unset stones direct from miners on the field, or from brokers there. While this may reduce the cost of the opal, it also relies on your own knowledge and skills to correctly evaluate your purchase. All opals purchased, except for low value stones, triplets etc, should come with a certificate of authenticity, just as with other precious gems. Most stores will sell tax-free if you live outside Australia; just take your passport and airline ticket with you when purchasing.
If you are considering buying a stone for setting later, you should be aware that many jewelers outside Australia are unable or unwilling to work with opals. They often believe the relative softness (compared to diamond and some other gems) makes them prone to chipping and cracking, and so won't take the risk of cutting or setting them (Australian jewelers don't seem to have a similar problem, and this concern is certainly over-done). The skills required to confidently set opals are not as widespread outside Australia, nor is the experience working with opal. If purchasing an unset stone is your plan, you might want to find your jeweler first, and discuss your options before your trip to Australia and your purchase. On the other hand, most of the opal outlets in Australia have associated jewelers who can set your stone in a standard or custom piece within a few days. If you want a custom piece, have a design in mind, or perhaps already have some other gems such as diamonds that you want to set with the opal, you can take these with you, visit your opal store at the start of your trip, then collect the finished piece a little later, or have it sent to you once you return home.
If you have an heirloom opal that you want reset, your trip to Australia could be the ideal time to do so. Remember, if you take any jewelry or gemstones with you, make sure you get a Customs declaration form before leaving so these are not subject to duty on your return.
Caring for your opal
Opal is softer than some other common ring gemstones, and so needs somewhat greater care. Although still hard, about the same as or a little harder than hard glass, opal is not an all day everyday ring stone, like a diamond or sapphire. Don't do the dishwashing with your ring on, especially with doublets and triplets as the glue can be susceptible to water (rain and similar events are not a problem). While solids are actually OK in water, avoid very hot water, especially a combination of having your hand in hot water, then searching around in the freezer. The problem for solids with dishwashing is the possibility of hard knocks, not the water itself. Same goes for working in the oven, then a freezer. Don't use abrasive cleaners on opals, or ultrasonic cleaners even on solids as they could possibly cause cracking, but especially not on triplets or doublets as they may allow water penetration. If your opal has dulled over time, it can be cleaned using detergent and a cloth or a soft toothbrush. Experienced jewelers can re-polish opals to remove small abrasions and marks, and restore the original brilliance.
Having said all that, opals are not as delicate as often made out to be, and with just normal care will last forever. After all, they are already at least 65 million years old.