When it comes to gemstones appearances can be deceiving and what looks at first glance to be a ruby can actually be a clever combination of glass and garnet.
Even when the stone is natural it may have had a little cosmetic help along the way.
For probate professionals this matters as the value of a gemstone depends on whether it is earth grown or lab grown and, if natural, whether it has had any artificial ‘tweaks’.
Doublets and Triplets: The Gemstone Sandwiches
One of the oldest tricks in the jeweller’s book is the assembled stone.
Think of it like a gemstone sandwich: a thin slice of something desirable such as opal or garnet glued onto a cheaper backing, sometimes topped with an extra clear layer of quartz or glass. A doublet is made of two layers, while a triplet adds the third clear cap on top to boost durability and shine. What looks like a large, luxurious stone is in fact a composite.
Victorian jewellers were masters of this technique. A sliver of red garnet fused to coloured glass could easily pass for a ruby in a dimly lit parlour. Opal doublets, still common today, use a dark backing to imitate the prized depth of a solid black opal. From the front they are convincing but viewed from the side or under a microscope the join is obvious.
Lab Grown Stones: Real, But Not Born of Earth
A diamond grown in a laboratory is still pure carbon crystal, with the same chemical make-up as a natural equivalent that has spent millennia under the Earth’s crust. It sparkles and cuts glass in just the same way, and to the naked eye is impossible to tell apart from its natural cousin.
Scientists can now produce flawless rubies, sapphires, emeralds and diamonds in a matter of weeks, often for a fraction of the cost, but collectors and many gemmologists will argue that such stones lack romance.
They are real stones, but without the geological backstory that makes natural gems rare and more valuable.
Natural Stones with a Little Help
Not every gemstone deception involves glue or a lab. Many natural stones are simply improved after leaving the ground. Heating can turn a murky sapphire a deep velvety blue, or a pale tanzanite into the vivid violet that buyers expect. Irradiation gives topaz its electric blues, emeralds are routinely oiled to mask fractures, and agate and jade have long histories of taking on dyes.
These treatments do not make a gem fake, but they do mean it has had a little cosmetic surgery which in turn has a negative impact on its value, so it is important to detect.
Diamonds: Even Sparkle Gets a Touch Up
High pressure, high temperature treatment can erase brownish tints or even create fancy colours. Fracture filling hides cracks with a glasslike substance so the stone looks clearer.
A treated diamond is still a diamond, but not quite an unaltered miracle of nature.
The Sliding Scale of Real
So where does that leave us? Gemmology works on a spectrum. At one end are untreated natural stones, pure and unenhanced. Then come treated gems, still natural but with a little help. Next are lab grown stones, chemically real but man made. And finally, outright imitations like glass or cubic zirconia, sometimes with a sliver of gemstones as is the case with doublets and triplets.
The trick is knowing where on the scale a stone sits and valuing it accordingly.
How Experts Tell the Difference
Spotting these import factors takes proper tools and training. A loupe or microscope reveals inclusions or growth lines that betray a gem’s origin. Refractometers and polariscope tests check how light bends, while ultraviolet lamps highlight telltale fluorescence. Even so, many treatments are subtle, and only a hands-on inspection can separate natural from synthetic.
When in Doubt, Get It Checked
A jewel may be natural, enhanced, synthetic, or something in between, and its value shifts accordingly.
With Swift Values you have direct access to gemmologists across the UK with decades of experience who can untangle these distinctions for you, taking one more thing off your desk.
This article was submitted to be published by Swift Values as part of their advertising agreement with Today’s Wills and Probate. The views expressed in this article are those of the submitter and not those of Today’s Wills and Probate.
