Diamond accents can make or break a piece of jewelry. They can be the difference between an awe-inspiring ring that flashes from across the room or one that simply does the job – no more, no less. In all types of accents, there's an increasing worry about lab grown diamonds making their way in unbeknownst to sellers. This is especially true for melee diamonds. Stores and customers alike want to know that what they're selling and buying are the real thing.
The Gemological Institute of America (GIA) has a process that includes a synthetic diamond detector to help unveil stones that don't belong with your natural diamonds. K. Rosengart also recently added diamond testing services to its repertoire.
Getting the Obvious Synthetics First
Necessity is the mother of invention, they say. So it is with processes the GIA uses to determine the “realness” of a diamond. Artificial diamonds have in some way or another been getting more and more complex over the last three decades, and this demands more complex responses.
Standard equipment for testing gems will ferret out the most obvious offenders. This includes many synthetics and treated diamonds. This doesn't catch all of them, so the next step is scientific testing equipment at the GIA.
Testing by Type
Let's start with types of diamond. Most natural diamonds are type Ia. They contain paired or clustered nitrogen. This is because of the age of natural diamonds. Over millions of years, the nitrogen has time to aggregate together. This is impossible to achieve with the technology used to create diamonds in labs.
By contrast, a type Ib diamond contains a scattering of nitrogen atoms that are each isolated. Type IIa diamonds barely contain nitrogen, and type IIb diamonds contain isolated boron atoms. These are all rare in nature, but can occur. Nonetheless, they single out these diamonds for extreme scrutiny.
Short-wave ultraviolet radiation and infrared spectroscopy are used as synthetic diamond detectors at this point. They can also highlight the method used to make artificial diamonds. Type Ib diamonds are rarely made using chemical vapor deposition (CVD) production methods and are more likely to be high-pressure, high-temperature (HPHT) diamonds.
Of course you know that a natural diamond takes hundreds of millions or even billions of years to form. Lab grown diamonds take several weeks. This leads to obvious differences in how each grows.
Most natural diamonds have octahedral crystals, while synthetics feature octahedral as well as cubic crystals. This is a tip-off that a diamond is likely synthetic as well. You begin to pair this evidence and yet more to come in order to determine if a diamond is synthetic.
HPHT growth patterns are very obvious. GIA lists the factors that reveal an HPHT diamond as “color distribution, fluorescence zoning, and graining patterns related to their cross-shaped, growth sector structure.”
Flux-metal inclusions are also common. This is because of the alloy that HPHT uses to grow diamonds. In fact, if they're numerous enough in an HPHT diamond, you can sometimes even pick that diamond up with a magnet!
Visible and photoluminescence spectroscopy are often used to make a positive identification.
HPHT diamonds also display an uneven coloration. This has to do with how their impurities form. It's true that some natural diamonds display some color zoning, but when it takes place on an HPHT diamond, the pattern is geometric. Color zoning doesn't form in geometric patterns on natural diamonds.
CVD growth patterns are different from HPHT, and in many cases more advanced. Their crystals form a tabular shape and have a dead giveaway: a rough, black graphite edge.
Under crossed polarizing filters, they display a specific type of banded stress pattern. This involves orienting a pair of polarizing filters at a 90-degree angle to each other. When natural diamonds form, they form what's called a strain pattern as a result of the intense stresses that help create them. CVD diamonds don't endure this same stress. What little strain they do experience is uniform. As a result their strain pattern is very weak.
Verifying the Tests
The GIA uses a range of advanced equipment to be able to inspect diamond accents and other stones, but redundancy is the key to being sure. Diamonds go through inspections and multiple tests using various pieces of equipment. It's a scientific process that demands verification. The GIA doesn't just want to know if a diamond's synthetic, they also want to know how it was made, what process was used, and what additional processes were used to eliminate the more obvious signs that it's synthetic.
They maintain one of the largest databases of diamond characteristics on the planet. Every piece of new information they put into it helps them identify the lab grown diamonds of the future. The goal is to stay ahead of the curve.
Most synthetics that are made are knowingly passed along as synthetic diamonds and sold with transparency, but that's not the case with all of them. It's crucial to ensure that suppliers, stores, and customers alike are all working off of the most thorough information they can have.
Automation of Testing
Obviously, diamond accents and specifically melee diamonds are very numerous and very small. The GIA uses an automated synthetic diamond detector to aid the testing for large batches of very small diamonds.
This still includes verification for diamonds that need a bit more personal attention to determine their origins, but it helps to make the process fast and efficient while maintaining pinpoint accuracy.
All melee diamonds supplied through K. Rosengart are carefully tested, so only 100% natural diamonds are supplied. The information is shared transparently so store owners can be absolutely sure of the quality they're receiving. This also empowers store owners to pass this transparency and confidence onto their customers when they make a purchase.