GIA Finds Lab-Growns, Simulant in Parcel of ‘Natural’ Sapphires
It offered a look at how synthetics and simulants “can be mixed with their natural counterparts to misrepresent a parcel,” the lab said.
According to a lab note written by Najmeh Anjomani in GIA’s Summer 2022 Gems & Gemology issue, its Carlsbad lab recently received four rough blue stones submitted as natural sapphires for identification and origin reports.
The largest weighed 48.63 carats. It was partially fashioned, GIA said, with evidence of polish lines on its surface.
Examination under a microscope revealed gas bubbles, distinct flow marks, and conchoidal fractures, while the polariscope revealed weak snake pattern bands. Its hydrostatic specific gravity (SG) was 2.48.
All these observations together suggested a glass imitation, GIA said, which was confirmed by comparing the infrared spectrum with that of man-made glass.
Two of the other submitted blue stones, weighing 9.17 carats and 6.21 carats, were “more convincing imitations of natural sapphire,” GIA said.
There was a resin coating their surfaces that resembled a matrix commonly seen on natural rough corundum. GIA said the resin started to melt when touched with a hot point.
And though their rough surfaces made it difficult to see inside the stones, GIA was able to observe a few gas bubbles through a transparent area.
It also performed Raman spectroscopy, the results of which matched corundum, and immersed the stones in water, revealing curved blue banding.
GIA said laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) revealed trace elements matching synthetic corundum. SG values were found to be 3.76 and 3.59, respectively, both of which are below the SG of corundum (3.9-4.05) and are a result of the lower SG of the surface resin.
The lab issued reports for both identifying them as lab-grown sapphires.
Finally, the fourth rough blue stone submitted weighed 8.46 carats.
It had a “frosted” natural surface that made it hard to see inside, but GIA said it was able to observe some natural-looking fingerprints and strong, straight “inky” blue banding.
The lab immersed the stone in methylene iodide to confirm the color zoning it saw was straight, an indication of a natural origin.
The Raman spectrum matched that of corundum, further confirmed by SG of 3.96.
GIA put the stone under shortwave UV and saw a medium chalky blue fluorescence.
LA-ICP-MS revealed a natural chemistry, including iron and trace elements such as gallium, vanadium, magnesium, chromium, and titanium.
Given its appearance, color zoning, and chemistry, the stone was identified as a natural sapphire, with its report noting it had been heated and was of Madagascar origin.
Anjomani said in the lab note that the four submitted stones provided an “interesting study of how synthetics and simulants can be mixed with their natural counterparts to misrepresent a parcel.”
The author noted, however, that “careful examination and standard gemological testing are usually enough to identify them correctly.”
The winners, picked by a group of judges and voted as the public’s favorite, will be announced in a webinar on Oct. 11.
Learn how to better serve your employees, customers and community by having a dynamic and supportive company culture.
The engravable piece is a perfect family heirloom.
Sponsored by Synchrony
The family business’ fourth-generation eponymous owner reflects on the milestone and the market today.
While ethical mining is essential to a diamond business, they represent only a fraction of the responsibility bestowed on jewelers.
According to Christie’s, the auction is its most important single-owner watch collection ever.
The association has also hired a new marketing manager and announced two staff transitions.
The topics up for discussion with lawmakers included inflation, rising interest rates, hiring challenges, and crime.
The pear-shaped fancy vivid pink diamond will lead the Christie’s Geneva Magnificent Jewels auction on Nov. 8.
There are three designs to choose from this year, all featuring animals drawn by kids who have had wishes granted through Make-A-Wish.
Fine jewelry comprised three of the auction’s top 10 lots, though it could not top her director’s chair or scripts from “The Golden Girls.”
A total of four suspects are now in custody with police still on the lookout for the remaining two.
From a “whodunnit” murder mystery to a permanent jewelry party, Duvall O’Steen and Jen Cullen Williams share a wealth of suggestions.
“Mountings 2023-2024” and “Diamonds & Gemstones 2023-2024” offer a vast selection of options to create custom pieces.
It follows Creative Director Lucia Silvestri as she crafts the brand’s high jewelry collections.
The competition takes place in tandem with TJA’s annual convention, known as the Texas Jewelers Roundup.
The limited-run collection features figures from Haring’s iconic street art on charms, bracelets, rings, and more.