Grading

GIA Finds Lab-Growns, Simulant in Parcel of ‘Natural’ Sapphires

GradingSep 07, 2022

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.

These four stones were sent into GIA’s Carlsbad lab as natural sapphires, but three of them are not. GIA determined they were, from left to right, a 48.63-carat piece of man-made glass, 9.17-carat and 6.21-carat lab-grown sapphires, and an 8.46-carat natural blue sapphire rough. (Photo credit: Annie Haynes)
Carlsbad, Calif.—The Gemological Institute of America found two lab-grown stones and a simulant in a group submitted to its Carlsbad laboratory as natural sapphires.

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.

This photo shows the curved blue banding visible in the 6.21-carat laboratory-grown sapphire after being immersed in water. (Photo credit: Najmeh Anjomani)
This photo shows the curved blue banding visible in the 6.21-carat laboratory-grown sapphire after being immersed in water. (Photo credit: Najmeh Anjomani)

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. 

 Related stories will be right here … 

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.” 

Brecken Branstratoris the senior editor, gemstones at National Jeweler, covering sourcing, pricing and other developments in the colored stone sector.

The Latest

AuctionsNov 23, 2022
This Sapphire Tiara Once Owned by a Danish Princess Is Going to Auction

The Dec. 1 jewelry sale at Bonhams-owned Bruun Rasmussen will have several other pieces of royal jewelry on the block.

FinancialsNov 23, 2022
Movado Lowers Guidance Amid ‘Uncertain’ Retail Environment

Its Q3 sales dipped as inflation took its toll on shoppers in the U.S. and Europe.

MajorsNov 23, 2022
De Beers Jewellers Is Popping Up in Connecticut

The temporary store is the result of a collaboration with Betteridge.

Brought to you by
Knowledge and Skills for Today’s Hot Topics

From laboratory-grown diamonds to design to country-of-origin, GIA's Alumni Collective™ has a seminar to suite your needs.

CollectionsNov 23, 2022
Piece of the Week: Rembrandt’s Turkey Charm

Charm fans will gobble up this festive “Piece of the Week” pick.

Weekly QuizNov 18, 2022
This Week’s Quiz
Test your knowledge of the latest jewelry news with this quick test.
Take the Quiz
AuctionsNov 22, 2022
Jewelry Recovered from Sunken ‘Ship of Gold’ Heads to Auction

The S.S. Central America sank in 1857 off the coast of South Carolina, carrying tons of gold from the California Gold Rush.

IndependentsNov 22, 2022
See the Greek Jewels Going to Auction for Charity

Several Greek jewelry designers have donated pieces to the annual Hellenic Initiative silent auction.

Brought to you by
Diamond Shoppers’ 2022 Holiday Wish List

Give your customers the best diamond buying experience this holiday season.

Events & AwardsNov 22, 2022
Hodinkee to Receive Gem Award for Watch Excellence

Plus, see this year’s list of nominees for the Jewelry Design, Media Excellence, and Retail Excellence awards.

SourcingNov 22, 2022
Head of Australian Miner Burgundy Diamond Resigns

The company announced the resignation of Peter Ravenscroft late last week, effective immediately.

SourcingNov 21, 2022
Provenance Proof Launches Online Marketplace for Traceable Gems

Debuting today, it is open to Provenance Proof blockchain users.

TechnologyNov 21, 2022
Version 2.0 of the NDC’s ‘Assure’ Directory Is Now Live

Assure is the program the Natural Diamond Council launched in 2019 to test lab-grown diamond screening devices.

MajorsNov 21, 2022
JK Findings Acquires Intercept Silver & Jewelry Care

Intercept Silver & Jewelry Care distributes anti-corrosion and anti-tarnish products.

MajorsNov 21, 2022
David Yurman Just Opened a Palm Beach Outpost

It’s located on famed shopping street Worth Avenue.

EditorsNov 18, 2022
9 of My Favorite Pieces from the AGTA Spectrum Awards Editors’ Day

Senior Editor Brecken Branstrator’s highlights include a chrome tourmaline ring, a giant opal necklace, and an American mined stone.

CrimeNov 18, 2022
Jewelry Store Security Guard Killed in Armed Robbery

Police in Calumet City, Illinois are looking for several suspects involved in the robbery of a jewelry store in the River Oaks Mall.

MajorsNov 18, 2022
AGS Adds Sumit Dangi to Board of Directors

Dangi is global chief financial officer and treasurer at Jewelers Mutual Group.

CollectionsNov 18, 2022
Piece of the Week: Tabayer’s ‘Oera’ Pendant

The brand’s signature shape is rendered in an autumn-appropriate color palette.

MajorsNov 17, 2022
Boucheron’s Magical Holiday Campaign Has Landed

“Boucheron Wonderland” showcases best-selling styles, high jewelry, and some familiar faces.

MajorsNov 17, 2022
At eBay’s New Pop-Up, Pre-Owned Luxury Goods Are Currency

The temporary space in New York’s Diamond District lets shoppers trade in one authenticated luxury item for another.

SourcingNov 17, 2022
De Beers’ Oct/Nov Rough Sales Total $450M

As in September, the company’s sales were up slightly year-over-year but down month-to-month.

AuctionsNov 16, 2022
One More Big Pink Diamond Heads to Auction, With $35M Price Tag

It follows a few other notable fancy color diamonds at auction this fall, with mixed results.

CollectionsNov 16, 2022
There’s a New Jewelry Destination in Greenwich, Conn.

Serpentine Jewels has branched out from its private jeweler beginnings to a ready-to-wear collection and a Connecticut townhouse.

WatchesNov 16, 2022
Rolex Names New Group President

A filing made in Switzerland shows Nicolas Brünschwig now holds the top position at one of the most popular brands in the world.

Events & AwardsNov 16, 2022
These Pearl Jewels Won the 2022 CPAA Design Competition

The Cultured Pearl Association of America held its 13th annual International Pearl Design Competition this fall.

WatchesNov 16, 2022
Accutron Watches Has Its Very Own Whiskey

The watch brand partnered for the second time with Hudson Whiskey on a limited-edition blend.

ColumnistsNov 15, 2022
Creative Connecting: Managing Customers’ Expectations During the Custom Design Process

A great custom design experience starts with listening to your customers, Duvall O’Steen and Jen Cullen Williams say.

×

This site uses cookies to give you the best online experience. By continuing to use & browse this site, we assume you agree to our Privacy Policy