Opals are one of the most remarkably beautiful gemstones in existence, which is why the opal market is rife with fake and synthesized specimens.
Of course, many wouldn’t mind purchasing a laboratory-grown opal, as they’re often more affordable and far less problematic, environmentally speaking.
But it’s always good to be able to tell the difference between the real deal and imitators just in case a nefarious seller tries to take advantage of you.
It’s relatively easy telling a straight-up fake from an authentic opal, but distinguishing between a real opal and a synthesized opal takes a keen eye and a few top tips that I’m going to be sharing with you right here, right now!
Stick with me, and you’ll be able to acquire your opals safe in the knowledge that they are what the seller claims they are — Let’s begin!
Testing Opals For Authenticity
Thankfully there are a number of ways you can test an opal for authenticity.
Price & Quality Claims
Before we dig into the more gemological tests in this guide, a lot of the time, all you need to assess the validity of a seller’s claim is to consider the price of the opal or opal jewelry.
Granted, opals aren’t the most valuable gems in the world, but high-quality specimens will still go for a pretty penny.
So, if the opal in question is surprisingly affordable, yet the seller is claiming it’s of high quality, things don’t really add up. It probably won’t be a total fake, but it will almost inevitably be a lab-grown gem.
Country Of Origin
Here’s an interesting fact for you… 95% of all natural opals are found in Australia, so if the seller suggests that their opals come from anywhere else, it should definitely arouse suspicion.
Don’t get me wrong; it’s certainly possible that they managed to source some from a legitimate alternative location, but I’d recommend you do a little digging to make sure that’s the case.
And while you’re snooping around, why not try to find some seller credentials or take a look at some customer reviews of their outlet on a third-party site or forum?
Bubble Bedlam
Visually speaking, opals are a particularly busy mineraloid, but if you look closely, other than the signature clash of pastel colors, there shouldn’t be much else at play.
If you can see some small air bubbles suspended beneath the surface, it’s most likely a replica made out of glass.
Color Chaos VS Structured Shades
Although chaos isn’t something we generally strive for in life, an entropic dance of colors is a great sign in an opal.
The higgledy-piggledy manner in which the colors play against one another is one of the most enchanting aspects of these wonderful stones.
If, on the other hand, there seems to be some distinct structure in terms of color or pattern, It’s almost certainly a fake — Symmetry is a sure sign of a sham!
The best conditions to assess the color and pattern of opal is under a bright white light.
I’d also suggest analyzing your opal – or any gemstone for that matter – through a jeweler’s eye loupe, as this will give you a hyper-focused, hyper-magnified view of the color-flaking in your stone.
Color Depth
When you look at the alleged opal, where do the colors seem to spring from? Are they leaping out at you from the surface, or do they seem to stem from somewhere deeper in the stone?
The color of genuine opals will always shimmer playfully on the very surface of the gem.
If the color is restrained beneath a clear surface, it’s a sign that it may have been implanted into an alternative material.
Again, it’s best to assess the nature of opal colors under a bright white light.
Black Backings
If the opal seems to have a black backing, it’s not an opal at all. These are what are known as doublets or triplets. They do include a little sliver of opal, but that’s all.
Doublets are completed by a black backing, while triplets are completed by a black backing as well as a plastic or glass dome.
To check if you have a doublet on your hands, view the opal from the side, and if you can see a straight line spanning the perimeter of the stone, it’s definitely a fake.
To identify a triplet, inspect the opal from all angles and try to catch a glimpse of the black backing.
Should you be looking for real, quality opals, stay away from this sort of design, as it’s a sure-fire way to wind up disappointed and out of pocket.
The Density Test
Synthetic opals can look incredibly natural, but there are ways you can tell a real opal dug from the earth and a man-made opal grown in a lab apart.
One such way is the density test. It’s pretty conclusive, but you do have to have a certified genuine opal around the same size as the potential fake to give it a go.
Synthetic opals aren’t quite as dense as the real deal, which means they’re noticeably lighter, so if your certified opal seems heavier than the unknown opal, the unknown opal may well be the product of gem synthesis.
If you’re working with quite small specimens and you can’t tell the difference in weight just by holding them, you can do a specific gravity test, which goes a little something like this…
- Grab a set of scales accurate to at least a couple of decimal points.
- Weigh each of the opals and make a note of the results.
- Fill a cup with enough water to fully submerge your stones.
- Weigh your cup of water and make a note of the result.
- Suspend your certified opal in the water and note down the change in weight. This isn’t actually the weight of the opal, but the amount of water displaced by the stone.
- Do the same with your unknown opal and note down the results.
- Next, take the actual weights of the opals and divide them by the weights attributed to water displacement, and that will give you the density of the stones.
The UV Test
Another fantastic way to separate natural opals from their lab-grown counterparts is to blast them with UV light. The real specimens will fluoresce wildly, while the lab-grown opals will not appear quite as brilliant.
Final Thoughts
Opals are absolutely a gem to get excited about, which is why it’s so darn disheartening to get lumped with a fake, but take heed of the points discussed above, and you’ll be all but hoodwink-proof!
If you still feel unsure as to the provenance of your opal, don’t hesitate to contact a professional jeweler, as they’ll most likely inspect the stone for authenticity free of charge.