Like other precious gems, opals need the proper care to help them remain lovely for as long as possible. If you own an opal ring or other opal jewelry, read on to learn more about opals, how they are special, and their proper care and storage measures.
How Are Opals Different from Most Gems?
Many gemstones occur as crystals, and are often cut into faceted gems. Their predictable crystal structure allows a lapidarist to successfully plan and execute a faceting plan.
Other gemstones are generally not cut into faceted gems, and typically do not have a crystalline structure that can be “seen.” Prior to the invention of the microscope, these gems were thought to be internally amorphous. Through microscopy, it was discovered that these gems do have internal crystals, it’s just that they are so small they cannot be seen by the unaided eye. These gems are considered “microcrystalline.” And gems with crystals so tiny they require very powerful magnification in order for crystals to be discerned are called “cryptocrystalline.”
There are three important gem types that the ancients correctly considered amorphous: natural glass (moldavite and obsidian, among others), amber, and…opal. Opal is truly non-crystalline. It has no predictable internal structure.
Like other gemstones, opals come in many different colors and levels of transparency. But, the magical thing that opals can possess is “play-of-color.” This is that magical dance, of one or more colors, that you see when you move what is known as a “precious opal.” The flashy play-of-color seen in precious opal is highly desirable, rare, and valuable.
There are many opals that do not have play-of-color, too. Opals without play-of-color are sometimes called “common opal," but that in no way means they are not beautiful. For instance, fire opal is the one type of opal that is both transparent and lacking in play-of-color; but talented gem cutters can facet these fiery orange-to-red gems…so there’s nothing “common” about them.
In addition to those features, another characteristic of opal that is unique in the gem world is its actual chemical composition: SiO₂·nH₂O Hmmmm, do you recognize something in there? Yep, H₂O–-water! SiO₂ is silica. (The “n” is indicating that the quantity of water can vary.) So opal is actually a hydrated form of silica. In terms of internal structure, randomly different-sized spheres of silica, packed together, leave weird gaps between them. Those gaps are filled with water. From the time they are mined, opals start losing their water, which provides internal support.
Opals are Porous
And those "gaps” between the silica spheres reach the exterior of any opal gem. So, you guessed it–-opals are porous. In addition to trying to keep the natural water from leaching out, it is important that you don’t allow opals to soak in anything that would be harsh or destructive, since those fluids can penetrate into the opal, as well-–thereby doing permanent damage.
The Gaps in Opal Create the Play-of-Color
A transparent or translucent opal’s play-of-color comes from what happens to light as it bounces around in and between those water-filled (or dehydrated), weirdly-shaped, voids. White light is broken up into one or more of its spectral hues, and each color refracts at a different angle through the opal. The bodycolor of the opal (white being most common; but also gray, black, and other colors) combined with the crazy light show makes for infinite combos of flash and visibility.
Most people have heard that opals are “delicate,” and it is that randomized internal non-structure, especially once thoroughly dehydrated, that allows for easy breakage. There is no other gem quite like it in that regard, and hence their care is different from other gems.
Solid Opal versus Assembled Opal
Now that you’re better acquainted with how opals differ from other gemstones, it’s a good time to tell you about the common ways that humans manipulate opals to combat some of their delicate nature.
Typically, these manipulations are only employed if the natural opal material available, while possessing beautiful play-of-color, is too thin (or perhaps partially cracked) to expect it to survive either the stone-setting process or the stress of being subjected to human wear.
What is Solid Opal?A natural opal, simply shaped and polished, is referred to as “solid opal.” There are many, many varieties of solid opal, ranging in bodycolor, transparency, and amount of play-of-color. Here’s just a few varieties that fall under this category:
- White opal
- Black opal
- Crystal opal (even though it’s not a crystal!); also called water opal
- Fire opal
- Peruvian opal
- Hyalite opal
- Hydrophane opal
What is an Opal Doublet?Now imagine a thin slice of opal with beautiful play-of-color. Since it’s too thin to wear on its own, it will be made into a doublet. With a doublet, the natural slide of opal is glued to a black material (generally dyed black chalcedony, but black jade or other dark materials that are synthetic can be used, as well). In addition to providing stability, the black background allows for a very strong relief, allowing the play-of-color to have maximum “pop.”
Opal Triplet = Opal Doublet Plus a Top Layer
Mother Nature’s Opal Doublets
It’s not hard to understand how adding a stabilizing layer to the underside (and possibly top) of a very thin opal would allow a jeweler to make fixed shape and size assembled opals to use in mass-production. As a jewelry designer, that actually makes me want to yawn. Once of the additional beautiful qualities of opal are the random shapes in which they occur.
But, how can you behold the beauty of natural precious opal without investing in a large, solid opal? Enter boulder opals, Yowah and Koroit nut opals, and matrix opals! With these opals, the host rock into which the opal material intergrew, is left intact. So, in addition to showing beautiful play-of-color, it is contrasted to its adjacent material, which has a rustic, “just a rock” look to it.
Since the opal has been left intact with its host rock, this type of thin opal material possesses some of the stability that man-assembled opals have, but without the unpredictability of glue or cement to hold it together.
Opal Care and Opal Jewelry Care
If a piece of jewelry contains one or more opals, you simply care for it as you would a loose opal, since the opal is the most delicate material involved. Only have your opal jewelry cleaned professionally, since it cannot involve anything caustic. So, whether you own silver opal jewelry or gold opal jewelry, the cleaning cycle will be the same.
First, determine if your opal is solid, doublet, triplet, or boulder/nut/matrix. If you can see the underside of your opal and you see a solid black or other dark material, and that underside is relatively flat, then you have a doublet or triplet in your hands.
Boulder/nut/matrix opals tend to show their ironstone or other matrix from the top view as well as their profiles or undersides.
We’ll start with solid opal.
How to Care for Your Solid Opal
As you’ve learned, opals become more delicate as they lose their hydration. Since a solid opal has no backing (whether man-made or natural) of a more stable material, your best offense is a good defense, since once the water departs an opal, there is no way to replenish it.
Ideally, you should store your solid opals and solid opal jewelry in an airtight container of distilled water. Not tap water, not spring water, not any other kind of water. Distilled water. Storing in this manner keeps the water that is already present in the opals, in the opals.
While not as plentiful as they once were, 35mm film canisters make an excellent storage space for smaller opal rings and pendants.
FUN FACT: certain kinds of water opal (most notably Ethiopian hydrophane opal) soak up water readily, and some of them go almost colorless in the process. They also lose the water they soak up in a matter of a couple weeks, and then their color returns. As a consequence, it is very difficult to get a solid weight on an Ethiopian opal. Storing them in water is fine–just don’t be thrown off by the change in how they look when doing so!
What to Use For Cleaning Solid Opal RingsSolid Opal may be cleaned in warm water and super-mild detergent with a soft cloth. Keep away from household cleaners like bleach and other chemicals. Generally speaking, common jewelry cleaner is not suited to cleaning opals. Be sure to rinse off under running water any detergent you do use, and dab dry with a tissue.
How to Care for Your Boulder, Nut, or Matrix Opal
In the case of boulder, nut, and matrix opals, the opal layer is stabilized through the host rock being left intact. So, there’s no cement to concern yourself with. If possible, treat these opals as you would solid opals: by storing such opals and jewelry made with them in distilled water.
Cleaning Boulder, Nut, or Matrix Opal JewelryBoulder, nut, and matrix opals may be cleaned using the same opal cleaning cycle as solid opals: in warm water and super-mild detergent with a soft cloth. Keep away from household cleaners like bleach and other chemicals. Be sure to rinse off under running water any detergent you do use, and dab dry with a tissue.
How to Care for Your Man-Assembled Opal
In addition to possessing a delicate and thin layer of opal material, opal doublets and triplets also have the additional layer or layers of material affixed to the opal layer. The non-opal materials are never as delicate as the opal itself, so that does not present an additional concern to a solid opal.
But, the cement or glue itself is something that can make caring for an assembled opal a little trickier. There is such a tiny amount of cement used in assembling a doublet or triplet, that just minor effects on it can cause the adhesive to release. So, unfortunately, one should not store an opal doublet or triplet in distilled water. The stability that is gained in having a man-assembled opal means you can’t use the distilled water trick to keep the opal layer hydrated.
How to Safely Clean Jewelry with Opal Doublets or Opal Triplets
It is OK to use a moist towel and mild detergent to clean doublets or triplets, but they should never be submerged or soaked.Be sure to rinse off under running water any detergent you do use, and dab dry with a tissue.
Opals should not be cleaned using standard jewelry cleaner used for diamonds and other non-porous gems.
No Ultrasonic or Steam on any Kind of Opal
You’ve probably gathered by now that a professional jeweler’s powerhouse cleaning go-to’s–namely, the ultrasonic cleaning machine and the high pressure steamer–are not appropriate for opals.
Ultrasonic cleaners may cause cracks in solid opal and water penetration in doublets and triplets. And steamers can cause the exact same problems in opals. Without these powerful cleaning devices available to use on your opal jewelry, your best care always involves avoiding letting dirt accumulate on your opal pieces.
Do NOT Use Oil on an Opal!
Opals are soft enough that they are very easy to scratch. A large series of scratches starts to make a solid opal look dull or cloudy, and the play-of-color is dampened. The only solution for this is to have your opal professionally repolished.
But a common “solution” to this problem, which actually ruins opals by dehydrating them, is to apply oil to your opal. I’ve heard it all: kokui nut oil, baby oil, mineral oil….<sigh> Applying oil to an opal kills it. Don’t do it! Your Great-Aunt Myrtle is 100% wrong about it.
What if My Opal Ring Gets Scratched?
If your Opal loses its shine or gets damaged, return it to a qualified opal cutter. The dazzling luster of an opal fades with time due to little scratches. A competent polishing may rejuvenate a dull or damaged opal.