NEW YORK – December 3, 2019 – Researchers at Gemological Science International (GSI), one of the largest gemological organizations in the world, witnessed a case of extreme color instability of a CVD diamond within its laboratory testing facility.
During standard testing procedure, a 2-carat CVD diamond in GSI’s laboratory was exposed to high powered UV rays and went from near colorless to blue color.
The stone then was returned to the vault and stayed in it for a week and a week later the stone still retained the blue color. While it’s known that CVD diamonds can change colors under this type of ultraviolet light or extreme heat, typically a diamond of this variety returns to its normal color after 30 minutes to an hour of direct sunlight. The GSI lab team discovered that under standard ambient lighting conditions, this particular stone took two and a half hours to return to normal color.
Though the GSI team stresses that most CVD diamonds do not change to this extreme, they emphasized the importance of lighting conditions when color grading diamonds.
“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,” said Nicolas Del Re, Chief Information Officer of GSI. Based on these findings, he notes that color changes may happen through casual use as well.
“When wearing out in the open, CVD diamonds may change in coloration upon even subtle exposures to electromagnetic radiation such as UV rays on a sunny beach or under a blacklight in a nightclub for example,” said Del Re, noting its due to Photochronism. “We have the electrons in defects within a CVD diamond causing the energy state to change and in turn affect the way color is absorbed on the visible spectrum.”
About Gemological Science International (GSI)
Gemological Science International (GSI) is one of the largest gemological organizations in the world. Founded in 2005 in New York City, it has since grown to have 13 gemological lab facilities spanning four continents. Utilizing leading-edge processes and proprietary technologies, GSI provides manufacturers and retailers globally with a wide range of gemstone identification and grading services. The company is committed to advancing gemological research through its Research Center, and it offers gemological educational programs for trade professionals and the public at all levels.
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”.