Seema Athavale, Chief Gemologist, serving in Research & Development capacity with GSI contributed to an article in International Research Journal of Engineering and Technology on RAMAN Scattering: Fingerprint for Identification of nature and color origin of pearls
Considering Pearl to be the only gem that is created by nature without human assistance to enhance its beauty, Athavale explains the color of the pearl is determined by host mollusc. Laser Raman spectroscopy helps in the identification of the primary matrix, as the external features are the same in all types of pearls.
Raman spectroscopy is also used to determine pearl’s nature of origin, as to natural, cultured, dyed pearls, irradiated pearls, and imitation pearls. Raman scattering is used to detect natural pigments on pearls and in some cases to detect color treatments. All the pearls present the characteristic peaks of aragonite at 702 cm-1 (normally a doublet at 701 and 705 cm-1 depending on the resolution used) and 1085 cm-1. Natural Colored FWCPs peaks at around 1132 cm-1 and 1530 cm-1 which are characteristic of polyenic pigments. Color characteristics also differ according to the mother oyster species. The phenomenon of iridescence that shows glittering of various colors in a pearl is due to the interference and diffraction of light interacting with the specific structure on the pearl’s surface.
To read more on pearl research published in IRJET click the link here:
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”.