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Tips For Appraising Jewelry With Lab-Grown Diamonds |  September 14, 2020 (0 comments)


Horsham, PA—As lab-grown diamonds become more prevalent in the marketplace, jewelers are more likely to encounter them in pieces brought in for appraisal. Image: GIA's ID-100 diamond identification device. ©GIA.

Centurion recently offered a special jewelry appraisal webinar in conjunction with the National Association of Jewelry Appraisers (NAJA), featuring David S. Atlas, president of D. Atlas & Co. Inc., Horsham, PA, who also serves as NAJA’s associate director and chair of ethical issues. Atlas, a GIA graduate gemologist, a NAJA certified senior member, and a master gemologist appraiser of the Accredited Gemologists Association, offered a series of tips and blueprints for jewelers and appraisers to use when evaluating a piece of jewelry that may contain lab-grown diamonds.

Related: Doing Appraisals Correctly During and After COVID-19

When it comes to identifying manmade diamonds, Atlas says err on the side of caution and don’t overestimate your abilities.

“It’s become very technical. And while you may have bought a lot of equipment to do this work, if you don’t do it all the time you’re not going to be nearly as good at it as people who do it every day in the major labs. I see an opportunity for many appraisers to get in trouble,” he warns. 

That doesn’t mean you should give up and not do appraisals on diamond jewelry. Screening for man-made diamonds—as opposed to identification—is something jewelers can do fairly easily and it’s an extremely valuable tool in providing an appraisal, says Atlas. Atlas recommends jewelers learn how to rapidly screen for potential manmade diamonds in the D-J color range, the most common. It’s a useful skill, he says.

Jewelers will need a few simple and relatively inexpensive pieces of equipment: an ultraviolet transparency and fluorescent diamond screening tool, and a sample manmade diamond and synthetic colorless sapphire to keep as master test stones to ensure the tester is in working order. The sapphire can be used with the transparency tester and is less costly than the manmade diamond, he says.

Appraisal expert David Atlas.

“I do consider a control stone to be a must-have item for all electronic testing equipment,” he stressed.

“Obtain a good UVC lamp and look for fluorescence. It appears that if you see near colorless diamonds that have slight blue or stronger ultraviolet fluorescence, it’s likely natural. When you see a stone with short-wave fluorescence, then look for long-wave fluorescence. A stronger short-wave screening reaction than long-wave is an indicator of a manmade diamond.” 

Here’s why. Light below 400 nanometers is ultraviolet. 365 is longwave and 265 is shortwave. Manmade diamonds allow UV light even in the shortest waves to pass through, whereas mined diamonds of the typical Type 1A D-J colors most common on the market are opaque to shortwave UV but transparent to longer wave UV. That’s the difference. 

“It’s an invisible thing but there’s a sensor in the device that knows UV light is being transmitted through the stone. It gives immediate results. If it sees transparency, it says that’s a 2A type diamond. Even when it’s a synthetic sapphire, it thinks it’s a 2A type diamond.” Atlas says it’s a valid test for that color range and a very valuable screening tool—emphasizing that it indicates the need for further lab testing.

UVC lamps are now becoming commonly available because of the COVID-19 situation, he says. They’re also used for sanitizing surfaces because they kill viruses. He believes they’ll be easier to buy than they were before. But he warns jewelers to take personal precautions. “Short wave UVC is damaging for eyes and skin. Wear blackened glasses and get your hands out of the target zone,” he cautions. 

He also recommends jewelers watch the recent GIA webinar about separating manmade diamonds from natural, and to look up Branko Deljanin’s tools and books (Gemmological Research Industries, North Vancouver, BC, Canada). Those also cover the subject thoroughly and are compatible with the GIA information, says Atlas. 

Insurance value reports vs. fair market value reports.Fair market value appraising requires a higher level of expertise than screening for lab-grown diamonds for common insurance for a lower-value piece, says Atlas. “But at some point, you have to draw the line and say ‘I don’t know what you have; I can’t test adequately here, and we’re going to have to get it tested and get a report or I can’t write you a report.’”

For fair market value work, he says it still won’t matter if a two-point diamond in a big piece is manmade and the rest are mined—but it does matter when an important center stone can’t be identified as mined.

“You can’t assume that it isn’t mined or that it is manmade. You mustget a qualified lab report!” he stresses. “Don’t get caught by the temptation to make an assumption for tax purposes that carelessly reduces or increases the tax collection. “Someone might get in trouble with the IRS or might get sued by their client. That someone would be you.”

It’s not an appraiser’s role to guess when only a scientific finding will suffice, stresses Atlas. “Make your clients aware of this and they should be comfortable with your thoroughness. Don’t apologize for needing further documentation! You can’t shortcut this process when you’re making a sworn declaration to the parties that rely on those reports. You can be held accountable,” he warns.

Atlas is happy to assist in the process of creating statements for these kinds of evaluations. “After you save a few of these statements you’ll have a library to use as needed.” 

Updating prior reports to reflect current gold and diamond value. Atlas says if you’ve done a report on a piece previously, and you’ve seen the item before, you don’t necessarily have to see it again. While it’s always better if you can re-examine the piece in person, that might not be an option during the pandemic. 

“As long as you say that you examined it on a previous date and give that date on your report, it’ll probably be ok. But you can’t verify that the piece wasn’t damaged, or the stone is still secure, or the stone wasn’t switched, so there are shortcomings. But if they need to have insurance renewed and the insurance company will take it remotely, it should be ok.”

How to buy testing and screening equipment.What’s the best synthetic diamond screener for a retailer to buy on a limited budget?

The UV screeners that detect Type IIA vs Type IA all work essentially the same, and all are roughly around $500, says Atlas. “I bought one of those tools, nice and compact. I put a synthetic sapphire on the test surface, and it immediately told me it was a CVD or HPHT stone, so I knew that it functioned. They don’t identify natural vs. synthetic but they do a good job of screening and that’s really the beginning point.” Branko Deljanin offers tools to be able to make some identifications with some practice, and those also are fairly inexpensive, says Atlas.  

Beyond those basic pieces of equipment, Atlas says the GIA ID-100 is a device that will go a lot further with many diamonds. It identifies, not just screens, manmade diamonds, but is substantially more expensive: about $5,000 vs. the $500 or so for most of the UV testers. It identifies colorless to near-colorless diamonds, and now includes blue-to-green and brown diamond identification. A software upgrade that covers pink diamonds also is available.

“But when you step up from the $500 tool level you step into the $5000 tool level, and as far as I know there’s nothing in between,” Atlas says. He also cautions that as technology evolves, equipment bought today may become obsolete in the future. “Still, it’s a worthwhile investment if you can. Being able to screen natural from manmade is important for jewelers.”

Atlas also emphasized the importance of distinguishing between testing and screening. He defaults to the term screening. “If I’ve screened it and come to an analysis I can use to that it’s a natural stone, I’ll say I screened it with an electronic tester.” He says it’s not essential to put the brand name of your tester in the report, although “if you’ve invested in the ID-100 or something even more expensive, it’s worth bragging that you have this fabulous piece of equipment.” 

Atlas offers sample templates for appraisers and jewelers to use and is willing to share. Contact him at

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