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
TrendsOct 31, 2025
Piece of the Week: A Spinner Fit for ‘Frankenstein’This “Mother Father” spinner necklace from Heavenly Vices Fine Jewelry draws inspiration from Victorian Era jewelry.
CrimeOct 31, 2025
5 More Arrested in Louvre Heist, Jewelry Still Missing The suspects were rounded up in Paris and its suburbs on Wednesday night, but none of the stolen jewels were recovered with them.
Recorded WebinarsOct 31, 2025
Watch: How to Master Google Reviews for Your BusinessExperts share top tips on how to encourage positive reviews and handle negative feedback.
Supplier BulletinOct 30, 2025
Protect Your Customers and Your BusinessSponsored by the Gemological Institute of America
Weekly QuizOct 30, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
CrimeOct 30, 2025
29-Year-Old Man Charged in Multiple Seattle-Area Smash and Grabs The suspect faces charges in the August robbery of Menashe & Sons Jewelers and is accused of committing smash and grabs at two pawn shops.
Lab-GrownOct 30, 2025
Alison Lou’s New Collection Uses Lab-Grown Diamonds and ResinThe “Lumière Fine” collection was born from designer Alison Chemla’s interest in the transformative power of light.
Brought to you by
DESERT DIAMONDS: The Newest Trend in Natural Diamond JewelryFrom sunlit whites to smoky whiskeys, introduce your clients to extraordinary diamonds in colors as unique as their love.
TrendsOct 30, 2025
Amanda’s Style File: A Haunted HalloweenShow off your spooky side with these 12 festive jewels.
Events & AwardsOct 30, 2025
Jewelers Mutual to Host Jewelry Panel at Frazier History MuseumThe “Brilliant & Beyond” panel coincides with the “Love & Marriage” exhibition curated by Davis Jewelers in Louisville, Kentucky.
Events & AwardsOct 29, 2025
October Brings Little Change to Consumer Confidence Consumers are feeling more optimistic about their present situation while the short-term future remains a little scary.
Events & AwardsOct 29, 2025
Couture Partners With Time to WatchesThe company, which organizes a watch show in Geneva every spring, will bring a selection of watch brands to the 2026 Couture show in Vegas.
TrendsOct 29, 2025
Beth Bernstein Releases Vintage Jewelry Guide“The Modern Guide to Vintage Jewellery” follows the evolution of jewelry design from the ‘30s to the ‘80s with buying and styling advice.
EditorsOct 29, 2025
Why Creepy, Crawly Bugs Inspire Beautiful JewelryFor her annual Halloween story, Senior Editor Lenore Fedow explores the symbolism behind spiders, beetles, and other eerie insects.
Events & AwardsOct 28, 2025
Meet the 2026 Gem Award NomineesNotable jewelry designers, members of the press, and retailers are up for an award at next year’s gala.
Recorded WebinarsOct 28, 2025
Watch: The State of the Jewelry Industry Leaders from Jewelers of America and National Jeweler discuss the gold price, tariffs, and more in this one-hour webinar.
CollectionsOct 28, 2025
Eriness Reflects on Life in ‘One of One’ CollectionAfter experiencing motherhood, growth, and loss, founder and designer Erin Sachse has created 10 irreplaceable jewels.
AuctionsOct 27, 2025
Napoleon Left This Brooch Behind, And Now It’s Up For AuctionIt is part of Sotheby’s “Royal & Noble Jewels” sale along with an ornate hair ornament and an old mine-cut light pink diamond ring.
CrimeOct 27, 2025
Arrests Made in Louvre Jewel Heist One of the individuals was apprehended at the airport as he was trying to flee the country.
MajorsOct 27, 2025
Target to Cut 1,800 Corporate JobsThe retailer, which has faced struggling sales in recent quarters, is looking to streamline its operations.
Events & AwardsOct 27, 2025
Hill Management Group Hired to Help Atlanta Jewelry ShowHill Management Group will oversee, market, and produce next year’s spring show.
AuctionsOct 24, 2025
Bonhams Under New Ownership, Top Executives ReplacedLondon-based investment firm Pemberton Asset Management acquired the auction house for an undisclosed amount.
CrimeOct 24, 2025
Video Emerges of Louvre Jewelry Robbers Fleeing the Scene The footage shows two of the jewelry heist suspects descending from the second floor of the museum and then escaping via scooter.
CollectionsOct 24, 2025
Piece of the Week: Wyld Box Jewelry’s ‘Ray of Light’ EarringsFounder and designer Rosanna Fiedler looked to a vintage Cartier clutch when designing the sunlight-inspired drop earrings.
FinancialsOct 23, 2025
Jewelry Sales Resilient Despite Struggles at LVMH, KeringThe luxury conglomerates faced a challenging Q3 amid geopolitical and economic tensions.
SourcingOct 23, 2025
Petra Diamonds Turns to Shareholders to Raise Capital The struggling diamond mining company, which owns the historic Cullinan mine, has launched a rights issue to raise about $25 million.
WatchesOct 23, 2025
‘Million Dollar Hip Hop Watches’ Recounts Watch HistoryThe book details the journey of watches as symbols of hard-earned success in hip-hop for artists like 2Pac, Jay-Z, and more.
