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
FinancialsMay 30, 2025
Movado’s Q1 Sales Slip Amid ‘Challenging’ Retail Environment The company plans to raise the prices of select watches to offset the impact of tariffs.
Policies & IssuesMay 30, 2025
Tariffs & Designers: Navigating Pricing in an Unstable EnvironmentBetween tariffs and the sky-high cost of gold, designers enter this year’s Las Vegas shows with a lot of questions and few answers.
CollectionsMay 30, 2025
Piece of the Week: Renato Cipullo’s ‘Hematite Blaze’ NecklaceDesigned by founder Renato and his daughter Serena Cipullo, it showcases a flame motif representing unity and the power of gathering.
Brought to you by
Clienteling Isn’t a Buzzword. It’s an Essential Business Model.More shoppers are walking out without buying. Here’s how smart jewelers can bring them back—and the tool they need to do it right.
Policies & IssuesMay 30, 2025
Trade Court Declares Trump’s Tariffs InvalidHowever, the tariffs remain in effect in the short term, as an appeals court has stayed the U.S. Court of International Trade’s decision.
Weekly QuizMay 30, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
CollectionsMay 29, 2025
Britney Spears Files Trademark for New Jewelry LineThe pop icon is one step closer to launching her “B Tiny” jewelry collection, a collection she first began posting about last fall.
Supplier BulletinMay 29, 2025
Inoveo Platinum Grain, Exclusively Distributed by StullerSponsored by Stuller
Brought to you by
Las Vegas Antique Jewelry & Watch Show: Showcasing the Most Collectible Merchandise from Across the GlobeGain access to the most exclusive and coveted antique pieces from trusted dealers during Las Vegas Jewelry Week.
SourcingMay 29, 2025
Grizzly Auctions 6,620-Carat EmeraldIt was featured in the miner’s latest sale, which brought in $24.8 million.
TechnologyMay 29, 2025
GemFind Launches AI Product Description SoftwareGemText AI uses artificial intelligence to generate tailored product titles, descriptions, and tags with jewelry-specific language.
MajorsMay 28, 2025
Graff Unveils New Las Vegas FlagshipThe 3,300-square foot location is the jeweler's largest store in North America.
CrimeMay 28, 2025
8 Convicted in Kim Kardashian Jewelry Heist TrialAging and with myriad health issues, none will serve time for their roles in robbing the billionaire celebrity at gunpoint in 2016.
CollectionsMay 28, 2025
NY Liberty’s 2024 Championship Rings Honor Historic WinThe WNBA team received rings imbued with meaning, from leaf motifs and its Liberty torch to the number of diamonds used.
MajorsMay 28, 2025
Andrew Rickard Named JBT PresidentA longtime executive at RDI Diamonds, Rickard has served on the JBT board for the past five years.
MajorsMay 27, 2025
MJSA to Become Part of Jewelers of America The two organizations have signed an affiliation agreement that’s expected to be finalized in the coming weeks.
AuctionsMay 27, 2025
Al Capone’s Patek Philippe Pocket Watch Back Up for AuctionThe platinum and diamond watch is part of Sotheby’s upcoming Important Watches sale.
AuctionsMay 27, 2025
182-Carat Paraíba-Type Tourmaline Sells for $487K Recovered in Mozambique, “The Kat Florence Lumina” was part of Bonhams’ Hong Kong jewelry auction held last week.
TrendsMay 27, 2025
Amanda’s Style File: Candy-Colored GemstonesGet a taste of the delicious candy-like gemstones in this Amanda’s Style File.
CrimeMay 23, 2025
JSA Shares Holiday Weekend Security Tips Amid Spike in BurglariesJSA’s Scott Guginsky provided a list of nine security measures jewelers should observe while locking up for the long weekend.
CollectionsMay 23, 2025
Piece of the Week: Bliss Lau’s ‘Bright’ RingFrom Lau’s “Love of a Kind” series, the engagement ring was inspired by the moon and holds a different meaning depending on how it is worn.
Supplier BulletinMay 22, 2025
How to Put Natural Diamonds Back in the SpotlightSponsored by GCAL by Sarine
CrimeMay 22, 2025
NY Jeweler Sentenced in Shoving Death of Colleague at IJO ShowDavid Walton will serve three years’ probation after an incident in a hotel bar led to the death of West Virginia jeweler David Ettinger.
FinancialsMay 22, 2025
Watches of Switzerland’s Full-Year U.S. Sales Climb 14% The retailer also provided an update on how the tariffs situation in the U.S. is affecting its business.
IndependentsMay 22, 2025
Adeler Jewelers Celebrates 50 YearsThe family-owned jeweler in Great Falls, Virginia, will be celebrating its golden jubilee with a year’s worth of events.
Events & AwardsMay 22, 2025
Jose Hess Design Awards Announce JudgesThe nonprofit elected five judges who will decide the winners of its design competition.
MajorsMay 22, 2025
MJSA Releases 2025-2026 Buyer’s GuideThis year’s edition includes articles on the favorite tools of notable designers, evaluating when to outsource production, and more.
CollectionsMay 21, 2025
Bulgari Highlights Its Colorful Past in Phenomenal ‘Polychroma’ CollectionThe jeweler’s high jewelry collection features extraordinary gemstones, like a 241.06-carat emerald and the world’s fourth-largest spinel.
