GradingJun 14, 2021
IGI Finds 6-Carat ‘Natural’ Diamond Is Actually Lab-GrownGradingJul 23, 2021
Lead Glass-Filled Lab-Grown Ruby Submitted to GIA
Though it’s unclear why someone would treat the material in that way, it’s important gemologists know it exists, the lab said.
A 3.53-carat lab-grown ruby treated with lead-glass filling (Photo by Diego Sanchez; © GIA)
Carlsbad, Calif.—GIA recently received a stone it rarely sees: a lead glass-filled lab-grown ruby.
According to a lab note from Forozan Zandi in the spring 2021 issue of “Gems & Gemology,” the stone was submitted to the GIA Carlsbad lab for identification.
Zandi said that while it’s common for the lab to receive lead glass-filled natural rubies, to their knowledge only one other lab-grown example has ever been submitted.
The recently submitted ruby was transparent to semi-transparent, oval mixed-cut, and weighed 3.53 carats.
GIA performed the standard gemological tests on the stone, finding that it showed the properties of a ruby, including a refractive index of 1.761–1.769, a birefringence of 0.008, a specific gravity of 4.01, a uniaxial optic figure, and a characteristic ruby spectrum via a spectroscope.
It also put the stone under magnification, which helped the lab confirm it was filled, according to the note.
With lead glass-filled corundum, the filling material has a refractive index very close to that of the host material to reduce the appearance of fractures. GIA said it’s effective and helps improve clarity of even very low-quality material to help make it marketable.
Fortunately, it’s also easily detected under magnification, the lab added.
The lab-grown ruby in question showed a couple of conclusive identifying characteristics for the treatment when put under the microscope: orange and blue flash effects and gas bubbles trapped in the fractures.
Magnification, however, didn’t reveal any inclusions that would indicate a natural or lab-grown origin.
But when it viewed curved growth lines in the DiamondView, which looks at surface fluorescence by illuminating with shortwave ultraviolet light, the lab saw the striae as chalky luminescent bands, confirming the stone was lab grown.
Ultimately, the lab note concluded: “While it is unclear why anyone would go to the trouble to treat a synthetic ruby with lead-glass filling, gemologists should be aware that such material does exist in the trade.”
Related stories will be right here …
According to a lab note from Forozan Zandi in the spring 2021 issue of “Gems & Gemology,” the stone was submitted to the GIA Carlsbad lab for identification.
Zandi said that while it’s common for the lab to receive lead glass-filled natural rubies, to their knowledge only one other lab-grown example has ever been submitted.
The recently submitted ruby was transparent to semi-transparent, oval mixed-cut, and weighed 3.53 carats.
GIA performed the standard gemological tests on the stone, finding that it showed the properties of a ruby, including a refractive index of 1.761–1.769, a birefringence of 0.008, a specific gravity of 4.01, a uniaxial optic figure, and a characteristic ruby spectrum via a spectroscope.
It also put the stone under magnification, which helped the lab confirm it was filled, according to the note.
With lead glass-filled corundum, the filling material has a refractive index very close to that of the host material to reduce the appearance of fractures. GIA said it’s effective and helps improve clarity of even very low-quality material to help make it marketable.
Putting the lab-grown ruby under magnification revealed high relief trapped gas bubbles and blue and orange flash effects. (Photomicrograph by Diego Sanchez, field of view 7.19 mm; © GIA)
Fortunately, it’s also easily detected under magnification, the lab added.
The lab-grown ruby in question showed a couple of conclusive identifying characteristics for the treatment when put under the microscope: orange and blue flash effects and gas bubbles trapped in the fractures.
Magnification, however, didn’t reveal any inclusions that would indicate a natural or lab-grown origin.
But when it viewed curved growth lines in the DiamondView, which looks at surface fluorescence by illuminating with shortwave ultraviolet light, the lab saw the striae as chalky luminescent bands, confirming the stone was lab grown.
Ultimately, the lab note concluded: “While it is unclear why anyone would go to the trouble to treat a synthetic ruby with lead-glass filling, gemologists should be aware that such material does exist in the trade.”
More on Grading
The Latest
MajorsSep 22, 2026
Foundrae’s Lawsuit Against Pandora Can Continue, Court RulesA federal judge denied Pandora’s motion to dismiss Foundrae’s claim for copyright infringement of its medallions.
ColumnistsSep 22, 2026
Peter Smith: Our Struggle With Emotional SellingPeople aren’t thinking rationally when they are buying luxury products, and we shouldn’t be selling them that way, Peter Smith writes.
IndependentsSep 22, 2026
Constance Polamalu Named to '40 Under 40' ListThe Baltimore Business Journal recognized the entrepreneur for her leadership in business and the jewelry industry.
Brought to you by
Meet Gemology’s Next Generation Microscope: GIA® Gemolite® NXT Professional EditionExperience gemstones with greater precision and comfort than ever before.
Events & AwardsSep 22, 2026
NYCJAOS Returns for Autumn EditionThe four-day show is slated for Nov. 19-22 at the Metropolitan Pavilion in New York City’s Chelsea neighborhood.
Weekly QuizSep 17, 2026
This Week’s QuizTest your jewelry news knowledge by answering these questions.
AuctionsSep 21, 2026
Ultra-Rare Cartier Cheich Watch Sells for $3.4M Offered at Sotheby’s Hong Kong, the one-of-a-kind white gold watch now holds the title of most valuable Cartier wristwatch sold at auction.
MajorsSep 21, 2026
Longtime Industry Executive Pamela Bernstein-Gulla to RetireBernstein-Gulla has been working in the jewelry industry for 40 years, most recently as chief engagement officer for Hill & Co.
Brought to you by
Your Piece Could Be the One Editors Talk AboutSubmit your pieces for a chance to win in this year's competition.
IndependentsSep 21, 2026
Bhindi Jewelers Moves Into New, Larger California StoreThe relocated Glendale store, now at The Americana at Brand, was designed to be a contemporary “timepiece haven” inspired by luxury resorts.
AuctionsSep 18, 2026
7.52-Carat Unheated Paraíba Tourmaline Sells for $1.3M at Sotheby’s The top lot of the auction house’s Hong Kong jewelry sale was an Art Deco Mauboussin necklace with ruby beads, which sold for $2 million.
Policies & IssuesSep 18, 2026
Tariffs, Retail Crime Top of Mind at JA’s Annual Fly-In Retailers and manufacturers headed to the Capitol this week to discuss tariff exemptions for diamonds and gemstones, among other issues.
CollectionsSep 18, 2026
Nanis Transforms Its ‘Boule’ Into a Mirror Our Piece of the Week is a pair of drop earrings from the “Sway” collection featuring Nanis’ first use of mirror-polished gold.
AuctionsSep 18, 2026
Noonans To Auction Medieval Gold Seal Ring Recovered By 2 FriendsTwo metal detectorists discovered the ring, which may have belonged to English noblewoman Matilda of Lancaster, in Suffolk.
Policies & IssuesSep 17, 2026
Tariffs on India Could Increase as Russian Sanctions Bill Heads to Trump’s DeskThe bill has a provision that allows the president to raise tariffs on countries that import Russian oil and gas to as much as 100 percent.
Events & AwardsSep 17, 2026
This Is the Winner of the 2026 Robert M. Shipley AwardThe American Gem Society presented the annual award to a former president of its board.
CollectionsSep 17, 2026
Cynthia Erivo, Zoë Chicco’s Jewelry Collab Is an Ode to TransformationThe “Chrysalis” capsule centers butterfly motifs representing growth, transformation, and the unfolding of who you are.
Events & AwardsSep 17, 2026
Louisiana Retailer Kevin Patton Wins Lifetime Achievement AwardJewelers of Louisiana presented Patton, the third-generation president of Pattons Fine Jewelry, with the award at its annual convention.
PodcastsSep 16, 2026
Episode 9: Remembering Cindy EdelsteinTwo special guests join the podcast to commemorate the 10th anniversary of the designer advocate, mentor, and author’s untimely passing.
CollectionsSep 16, 2026
Jessica McCormack, L’Objet Collab on Homewares CollectionMcCormack brings sea-inspired motifs from her “Beaches” collection to L’Objet’s tableware, vanity pieces, and first-ever cutlery set.
CrimeSep 16, 2026
JSA Issues Warning to NJ Jewelers After Rash of Smash and GrabsNine New Jersey jewelers have been victims of smash-and-grab robberies this year, prompting JSA to circulate a list of recommendations.
IndependentsSep 16, 2026
Bromberg & Co. Names New PresidentMarlin “Brian” Hood, who has been with the store for 20 years, will succeed Ricky Bromberg, who died earlier this month.
MajorsSep 16, 2026
Midas Chain Releases ‘House of Midas’ Bridal CatalogThe new bridal catalog features the latest jewelry collections and designs from timeless classics to modern silhouettes.
EditorsSep 15, 2026
2026 Emmys Jewelry: An Either/Or Proposition Stars wore either a necklace or earrings at 78th Primetime Emmy Awards but rarely both, Natalie Francisco notes.
ColumnistsSep 15, 2026
The Levels Your Website Must Clear Before AI Recommends YouJennifer Shaheen compares this new era of AI-powered SEO to a video game: your website must clear one level before advancing to the next.
IndependentsSep 15, 2026
Armadani Launches Retail Support Program for Holiday SeasonThe program highlights “Made in Italy” fine jewelry with digital merchandising, sales education, and local marketing support.
EditorsSep 15, 2026
Q&A: Signet Jewelers’ Joan Hilson on Diamond Demand, the HolidaysHilson, Signet’s chief operating and financial officer, discussed Q2, resurgent natural diamond demand, and why Blue Nile is a standout.
ColumnistsSep 14, 2026
Sherry Smith: Stop Waiting for December to Save Your ChristmasThe stores that have a great December are the ones that made good decisions in August, September, and October, Sherry Smith writes.
