Lab-grown diamonds grown using chemical vapor deposition (CVD) could change color for an extended period following exposure to certain light forms, Gemological Science International (GSI) has cautioned.
When testing a 2-carat CVD diamond, GSI exposed the stone to high-powered ultraviolet (UV) rays, during which it went from near colorless to blue. This blue coloring remained despite a week in a vault.
Although CVD diamonds are known to change color under strong UV lighting or extreme heat, they generally return to normal after 30 minutes to an hour of direct sunlight. However, the stone in question took two-and-a-half hours to return to its regular hue, it added, warning that color changes in CVD may occur through casual use.
The stones change color due to photochronism, a process by which the electrons in defects within the CVD diamond cause the energy state to change, thereby affecting the way color is absorbed on the visible spectrum, explained Nicholas DelRe, CIO – GSI
“It is strongly suggested that all laboratory-grown CVD diamonds are placed in a full-spectrum light box for at least 30 minutes before color grading,” Nicholas DelRe explained.
To read more on the article published by Jewellery Business Magazine Febrarury edition click on the link below
Jewellery Business Magazine page 42-44
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Nicholas DelRe is the chief information officer (CIO) of Gemological Science International (GSI). He nearly has four decades of experience working in research and gem identification departments of gemological organizations as well as serving in an R&D capacity with Industrial Diamonds. DelRe is presented at numerous functions within the jewelry industry, including NYC Mineral Club, where he has held office as secretary for many years. He can be reached via email at email@example.com
About the author
💎 Where is Gemological Science International (GSI) located?
GSI is headquartered in New York, NY. It has 13 laboratories on four continents and in a number of countries: the United States, India, Dubai, Israel, Belgium, Hong Kong, and Botswana. This makes GSI one of the largest independent gemological organizations in the world.
💎 Is there a difference between grading reports issued by different GSI laboratories?
All GSI laboratories grade using the same methods and adhere to the same standards. Every laboratory is staffed with highly trained professionals who have years of grading experience and an extensive gemological background.
💎 What does it mean when a sales associate tells me my diamond is “GSI Certified” or is accompanied by a “GSI Certificate”?
The phrases “GSI Certificate” and “GSI Certified” are industry shorthand for GSI grading or identification reports. What this means to you is that expert gemologists and trained professionals meticulously evaluated the item. When your diamond, jewelry or gemstone is accompanied by a GSI grading report, you can be completely confident in the accuracy and objectivity of the evaluation.
💎 Where can I find “GSI Certified Diamonds”?
GSI diamond grading and identification reports can be found in jewelry stores worldwide and online. Insist on a GSI grading report when shopping for a diamond, jewelry or gemstone.
💎 What do I do if I lose my GSI Diamond Report?
💎 What are the 4Cs
A beautiful diamond is one of nature’s most mesmerizing creations. But how do you objectively judge the quality of the gem? The 4Cs – Cut, Color, Clarity, and Carat Weight – are the universal standard for doing this.
💎 Is there anything beyond the 4Cs?
The 4Cs are an essential and important description of a diamond’s characteristics. But there is a considerable amount of detailed information behind each “C” along with other qualities of a diamond that affect its beauty, such as fluorescence, light performance and more.
How much do you need to know? That’s up to you, but knowing the 4Cs is almost essential.
💎 What does a GSI diamond grading report look like?
GSI offers a number of grading reports (often referred to as “GSI Certificates”). You can see samples of them by browsing the Grading Reports page on our website.
💎 What does a GSI colored diamond grading report look like?
You can see samples grading reports by browsing the Grading Reports page on our website.
💎 What does a GSI Colored stone report look like?
You can see samples of Colored stones reports by browsing Grading Reports page on our website.
💎 How does a GSI grading report compare to other laboratories that issue grading reports?
It is our policy not to comment on other laboratories. However, know that GSI adheres to the highest ethical standards. We do this in a number of ways:
- Rotating gemologists to our different labs
- Continuously upgrading our proprietary grading software to ensure full compliance with international grading standards
- Having our gemological research department constantly investigate new developments in the industry, which informs the grading process
💎 What’s the difference between a “GSI Certificate” and a “GSI Diamond Grading Report”?
GSI issues a variety of grading and identification reports. Consumers and industry professionals often call these reports “GSI Certificates”.