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Undisclosed 3-4ct laboratory-grown diamonds

Updated: Aug 11, 2023

By Julia Griffith FGA DGA EG

Founder & Course Creator


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Companies are losing money by accidentally purchasing undisclosed laboratory-grown diamonds from the public. You can learn how to avoid these buying mistakes! Let me tell you a true story about a jewellery retailer that buys-in diamond jewellery from the public domain...

Whilst window-shopping a local town, I noticed a 3.5ct laboratory-grown diamond ring for sale in a jewellery store...

3.5ct lab grown diamond ring undisclosed
The 3.5ct lab-grown diamond seen in the shop window

Soon after, I hosted one my practical workshops on Identifying laboratory-grown diamonds. One of the staff members from this local jewellery store attended! It turns out that this rogue 3.5ct laboratory-grown was purchased unknowingly. It was bought from a member of the public who claimed it was a natural diamond. Unfortunately, the staff members did not know how to identify laboratory-grown diamonds and only discovered the true identify of the stone after it was tested at the Gemmological Institute of America (GIA).

Stories like this are becoming increasingly common and many businesses that buy second-hand jewellery from the public domain are becoming victim to undisclosed laboratory-grown diamonds.

This store had learnt a hard lesson. I commend them for taking action by attending my practical workshop so that it would never happen to them again. This investment in education will save them ££££s by avoiding undisclosed laboratory-grown diamonds in the future. In fact, they saved thousands during the workshop as the staff member bought along two more large 'diamond' rings for us to test... read on to find out what happened!


Come join the practical workshop: Identifying laboratory-grown diamonds

Next workshop: August 12th


natural 4ct diamond halo ring
A 3ct natural diamond with no laser inscription

The two rings that were brought along to the workshop contained centre stones that weighed approximately 3-4ct each. The company was considering purchasing them from the public domain who claimed that these were natural diamonds within these rings. In my workshop, we could test them and find out whether they were indeed natural or undisclosed laboratory-grown diamonds.

Think all large diamonds are laser inscribed? Think again!

One may think that an important stone worth thousands of pounds would be laser inscribed, right? Wrong! Unfortunately, many large diamonds and laboratory-grown diamonds lack laser inscriptions entirely.

Not only did the undisclosed 3.5ct laboratory-grown diamond at the beginning of this story have no a laser inscription - but this was also the case for the two big 'diamond' rings that were brought along for testing during my workshop.


What did we discover about the two big 'diamond' rings?

Well... one was a natural diamond (hoorah!). The store purchased the ring with confidence at a great price. The other was a CVD laboratory-grown diamond. The company refused the offer of the laboratory-grown diamond based on the fact it was laboratory-grown (they could have purchased if they wanted to, but at the correct price for a second-hand laboratory-grown diamond).

The main test that allowed us to confidently identify the origin of these stones was the observation of UV reactions to both longwave and shortwave UV light - a skill I teach within the workshop whilst utilising the Jewellery Inspector by Gemetrix.

fluorescence in natural and lab grown diamonds - UV reactions from geometric jewellery inspector
UV reactions under LWUV and SWUV from the two rings. Left - CVD laboratory-grown diamond. Right - natural diamond

Not only did this retailer save thousands of pounds by avoiding the accidental purchase of an undisclosed laboratory-grown diamond - they also now have these skills for the future. They will save time and money by making faster purchasing decisions - without the need to send all stones to a testing laboratory as they can do much of the testing themselves. Most importantly - they can buy diamond jewellery from the public with confidence.


Come join the practical workshop: Identifying laboratory-grown diamonds

"The course was excellent. We learnt a lot about how to differentiate synthetic diamonds from natural using simple tools that most people in the industry have access to." - Louisa Guiness

Lessons to be learnt:

The main thing I learnt from this experience is that large laboratory-grown diamonds are circulating the market undisclosed without laser inscriptions. As laboratory-grown diamonds can be grown to even bigger sizes (undisclosed stones up to 15-16ct have been reported at testing laboratories), and where fraudulent laser inscriptions have also been reported, it is incredibly important to be able to detect laboratory-grown diamonds at your workplace. With the ever increasing number being produced - could you confidently purchase 'diamond' jewellery from the public?

If your answer is no - bravo for admitting it. You can boost your confidence and protect yourself, your business and your reputation from buying mistakes by joining my practical workshops and online courses.

In my practical workshop, we cover observation, screening, UV reactions and strain patterns of laboratory-grown diamonds. With knowledge and the correct tools, you will be able to identify more than 90% of the loose diamonds that come your way, as well as the majority of set stones. This means you can confidently make a purchasing decision in the moment, without sending the piece to a testing laboratory - saving time and money, and also looking like an absolute boss when it comes to identifying diamonds vs. laboratory-grown diamonds. Companies are now saving 1000s of pounds by avoiding buying undisclosed laboratory-grown diamonds from the public.

In regards to the member of public - did they know it was a laboratory-grown diamond and were purposefully trying to commit fraud? Or were they a victim that had been fraudulently sold a laboratory-grown diamond as a natural one? I don't know which one is worse. All I know is:

1) Laboratory-grown diamonds are prevalent.

2) Many are being sold back into the second-hand market by the public.

3) We have to protect ourselves through learning the necessary skills and knowledge so we can identify these stones.

Come and join my workshop and learn these important skills for yourself.

"If you work with diamonds, unless you've already done this workshop, you need to do this workshop. You don't have time to research and learn all this stuff yourself. Julia hands it to you on a plate. It's not cheap, but it's exceptional value for money, and in the long run will save you time, money and stress." - Kerry Gregory, Gemmology Rocks


Come join the practical workshop: Identifying laboratory-grown diamonds

Next workshop: August 12th


Learn all about laboratory-grown diamonds with my online course:


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