Opal: A Distinctive Statement Gemstone

With the recent trend toward engagement rings which feature gemstones other than diamonds, it’s no longer unusual to see a bride sporting a beautiful setting highlighting rubies, aquamarines, emeralds, sapphires, morganites or even pearls on her wedding finger. To truly stand out in the crowd, though, there’s no more gorgeous choice than an opal engagement ring which shines and sparkles while showing all the colors of the rainbow.

Opal has existed since the early days of man. Specifically, fire opals were a beloved gemstone in civilizations from Persia to Central America, particularly by the Aztecs and Mayans who considered it “the stone of the bird of paradise”, and the early Romans valued opals more highly than any other gem. There’s also a long and interesting history of many cultures shunning opals because they were believed to bring bad luck, however; sorcerers and witches were said to derive their powers from black opals, in medieval Europe the stone was shunned for its resemblance to the “evil eye”, it was bizarrely blamed for the Black Plague (because jewelers had supplied opals to many of the victims), and a common misreading of a novel by Sir Walter Scott led to a widespread belief that an opal bewitched and then caused the death of the heroine.

These feelings caused the opal to fall completely out of favor, only to be “rediscovered” in the mid-1800s when the stone began to grow in popularity. The use of opal flourished during the Art Deco period of the 20th century, and it remains an extremely popular jewel because of its ability to “play games” with color in fascinating ways. However, opal engagement rings are one of the last frontiers for use of the gem; we’ll discuss the reasons why, and examine the incredible varieties of this gemstone, after a quick look at the unique story of opal.

Opal Three Stone Slant Engagement Ring in 10K White Gold with Diamond Accents

Opal Three Stone Slant Engagement Ring in 10K White Gold with Diamond Accents / Zales.com

Australia’s “Queen of Gems”

The process of opal formation began millions of years ago when the huge sea that covered most of Australia receded, allowing the silica and water which remained in the rocks of the shoreline to slowly become transformed into the gel blocks later known as opal. The first “modern” discovery of the stone came in 1849 at a cattle station known as Tarraville, and shortly after that, mining began in earnest across areas of the country now known as the Australian opal fields. Even today, Australia is the primary source of fine opals, supplying about 97 percent of the gemstones. Smaller quantities come from Mexico, Brazil, a small area of the American Rocky Mountains, Ethiopia and Mali, but the majority of opals are still mined in specific areas of Australia.

There are many types of opal found in Australia, each primarily coming from a different Australian opal field. For example, the stunning and valuable black opal is mined at Lightning Ridge in New South Wales, while Coober Pedy and Adamooka in South Australia are the world’s major sources of crystal, white and light opal, and the unique boulder opal (attached, as its name suggests, to a rock) as well as colored opals are found in Queensland mines. However, many colored opals, as well as the amazing fire opal, are mostly sourced from Brazil and Mexico, with some fire opals also coming from America.

Heart-Shaped Lab-Created Opal and White Sapphire Three Stone Ring in Sterling Silver

Heart-Shaped Lab-Created Opal and White Sapphire Three Stone Ring in Sterling Silver / Zales.com

Types of Opal

One of the captivating features of precious opal is that so many of its colored varieties are enchanting. What they have in common is that they’re primarily composed simply of water and silica, and they diffract light because of their internal structure of the silica spheres which create the gemstones’ distinctive and intriguing play of color. What’s very different is the appearance of each of these stones.

The most valuable is black opal, which is usually a misnomer. Opals with a deep black color are extremely unusual; most are actually shades of dark grey, blue or green, or sometimes grey-black, with extreme color play evident in all of those shades. Dark black and dark grey stones are famed for their brilliant play of colors and are the most highly-prized of all, making black opal engagement rings an expensive but exquisite choice. The black color comes from inclusion of carbon and iron oxide in the stone, and it’s important to realize that “black opal” doesn’t literally mean that the stone is completely black when you look at it – since a 100% black stone would prevent the rainbow of reflected colors from being seen and would be worthless. In categorizing these stones, “black” refers to the general body tone of the gem. A top-quality black opal can cost $10,000 or more per carat.

Truly precious fire opals (there are many common fire opals on the market which don’t show the same color play) aren’t quite as pricey as their black cousins. But fire opal engagement rings may be the most stunning of all due to their fiery and radiant orange and red colors (created by iron oxide traces in the stone). The finest fire opals come from Mexico, as Brazilian stones usually show less play of color, and are sometimes cloudier with yellow or brown tones showing in the gem. However, the beauty of a fire opal doesn’t depend solely on whether or not you can see a rainbow of reflected colors, since the orange color makes a striking statement all on its own. The finest fire opals can cost as much as $2000 or even $4000 per carat, but many “lesser stones” are available at a quarter of that price or even less.

Crystal opal is not really a “color”. It’s the description of a stone which is more transparent than most opals, and has excellent color play because its structure allows lots of light to pass through it. Black or white opals which don’t exhibit all of the characteristics of those top-quality gemstones may be classified as crystal opals, which are a much more affordable choice at $1000 to $3000 per carat.

White (also called light or milky) opal, like its black cousin, isn’t truly the color suggested by its name. It is found in varying shades of pale white or grey colors, and is much more commonly found (and the least valuable) of all the opal varieties. The absence of darkness means that any colors which are reflected don’t stand out in the same way they would with a black or grey stone, making them less vibrant. However, top-quality white opals can still be quite beautiful with nice color play, and give white opal engagement rings an understated yet very classy appearance. There is often some crossover between crystal and white opals depending on the amount of translucence in the stone; some gems are actually classified as “white crystal opals”. The best white opals can be a relative bargain at $100-$200 per carat.

There are several other “natural” colors of opal, including olive, brown, slate, green, yellow and blue. Most do not display the pleochroism which causes color play, but are still very attractive and fairly inexpensive, and well-suited for outside-the-box pieces like blue opal engagement rings.

Cushion-Cut Lab-Created Opal and White Sapphire Frame Ring in Sterling Silver

Cushion-Cut Lab-Created Opal and White Sapphire Frame Ring in Sterling Silver / Zales.com

How Opals Are Valued

As we’ve already seen, color and color play in an opal are the primary factors in determining the value of these gemstones. In fact, there are many terms used to describe the optimal patterns of how color plays in an opal, such as church windows, harlequin, lightning and peacock, or needle fire. Experts will often use these terms in their valuation to describe the color play, with closely-spaced, large patterns preferable to widely-scattered, small dots. The range of the play of color is also a key consideration, with stones whose colors span the entire spectrum more valuable than those showing only a few secondary colors, and those whose display can only be seen from one or two angles less valuable than those whose color play can be seen from all angles. Also important is whether there are any “dead spots” in a stone, which hurt the gemstone’s value.

The clarity of an opal (how transparent it is, and whether there are inclusions) is another key to valuation, but it’s a more complicated consideration than with most other gemstones since different levels of transparency will affect color play differently in each type of opal. For example, more opaque stones are favored for black opals while crystal opals must be transparent in order to best display color. In any opal, cloudy backgrounds should be avoided. As with most gems, defects like crazing or large inclusions should be avoided as well.

Also important is the stone’s cut, since it is a major determinant in how vividly an opal’s play of color, or “opalizing”, will be displayed. Most white opals, and some finer stones, will be cut and then polished to either oval or round cabochons (or another shape with a soft dome) in order to enhance the opalizing of the ring. However it’s quite common for highly-valuable stones to be cut into more irregular shapes which optimize color play; those then must be placed into custom settings. In any case, the stone should be cut symmetrically and preferably low-domed, because opal is a very delicate stone (more about this shortly).

Opal Polished Sterling Silver Fashion Ring

Opal Polished Sterling Silver Fashion Ring / Ice.com

What You Need To Know Before Buying A Ring

Opal engagement rings certainly will stand out and make a lasting impression in ways most other rings won’t. However, whether you’re looking at antique opal engagement rings in upscale jewelry stores, considering somewhat “standard” fire opal, white or black opal engagement rings, or even working with a designer who creates one-of-a-kind opal and diamond engagement rings (a truly stunning combination), it’s important to understand that opals differ from precious stones like diamonds in several important ways: strength, durability and temperature sensitivity.

Diamonds are, of course, known as an exceptionally hard and durable stone. Opals, by contrast, are soft, weak and extremely sensitive to cold temperatures because of their high water content. While you can just put on a diamond ring and “forget” about it, an opal engagement ring requires very specific care and attention – something which must be carefully considered before taking the plunge and choosing an opal for something as important as an engagement ring.

First, the ring should be removed whenever doing chores around the house, taking showers, or doing anything which could expose the stone to contact with abrasives, chemicals or contact with another object, since the stone is easily cracked, broken or otherwise damaged. It’s also best not to wear an opal ring in cold temperatures, because sudden temperature changes can cause the stone to crack. Finally, opals should periodically be placed into an air-tight bag with a few moist cotton balls, because the gemstone dries out easily (another cracking hazard) unless it’s regularly placed in a humid environment.

None of that means that you should forget your vision of eye-catching black or fire opal engagement rings. It just means you need to make the commitment to care for your keepsake properly. There are also a few other steps you can take to minimize the possibility of damage to an opal engagement ring.

Perhaps the safest choice is a boulder opal for your ring; it won’t reflect light like a black opal, but its unusual natural shapes lend themselves to a unique piece, and it’s the type of opal least likely to crack or break due to its ironstone backing. In any event, you should always choose a bezel setting for an opal engagement ring. The gold bezel covers the edge of the stone to protect it against unexpected contact with other surfaces, and holds it firmly in place. We’ve also mentioned that the best cut for an opal ring is one with a low cabochon (dome), and this is the reason why – a stone which is low or has a flat top is less likely to come in contact with something which could cause it to break or crack.

With a proper understanding of how to care for an opal engagement ring, there’s no limit to the type of unique and spectacular piece you can create or purchase to mark an engagement or marriage. From vintage opal engagement rings to show-stopping black opal engagement rings, there’s no better way to symbolize life-long love than with this stunning gemstone.