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.”
Editors' Picks
Sponsored by
More on Grading
The Latest
MajorsMar 10, 2025
Terry Chandler to Retire After 24 Years as Head of DCA Chandler started his jewelry career at Michelson Jewelers, joining the Diamond Council of America as president and CEO in 2001.
CollectionsMar 10, 2025
MaeVona Co-Founder Debuts 3D-Printed ‘Tùsaire’ CollectionScottish American designer Maeve Gillies collaborated with Platinum Guild International on jewelry created by direct metal 3D printing.
Events & AwardsMar 10, 2025
The Jewelry Symposium Announces 2025 Scholarship WinnersAhead of its trade show in May, TJS awarded free registration and accommodations to five up-and-coming jewelry industry professionals.
Brought to you by
Natural Diamonds Should Mean MoreNatural diamonds mean more than lab-grown, but when every cut is ideal, they all look the same. Customers want more—Facets of Fire delivers.
Events & AwardsMar 10, 2025
These Designers, Journalists, and Retailers Are Up for a Gem Award The 2025 Gem Awards are set to take place Friday at Cipriani 42nd Street in New York City.
Weekly QuizMar 06, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
MajorsMar 07, 2025
Jane Fonda, Mariska Hargitay Star in Pomellato’s IWD CampaignThe annual star-studded campaign for International Women’s Day encourages collective action against domestic violence.
CollectionsMar 07, 2025
Piece of the Week: Yeprem’s ‘Golden Strada’ NecklaceThe statement piece is seen in Yeprem’s new “You Play the Game” campaign, created for International Women’s Day.
Brought to you by
Have a Plan for EmergenciesEmergencies can happen anytime, anywhere , and Jewelers of America has what you need to be prepared for it all.
MajorsMar 07, 2025
Borsheims Names New Senior Security and Facilities ManagerLongtime employee Kyle Slosson has been promoted to the role.
IndependentsMar 06, 2025
Wixon Jewelers to Close After 37 YearsFirst-generation jewelers Dan and Hope Wixon are retiring and will close their Minneapolis-area jewelry store in May.
CollectionsMar 06, 2025
Guzema, 3.1 Phillip Lim Collab on New ‘Snake’ DesignsThe limited-edition collection, a nod to the Year of the Snake, is Ukrainian brand Guzema’s first partnership with a U.S. brand.
IndependentsMar 06, 2025
Stephen Barnes Is the New Owner of IJOAfter more than 50 years, Jeff Roberts is handing over ownership of the organization to IJO President Stephen Barnes.
Events & AwardsMar 06, 2025
Borsheims’ ‘Ike-It’ Award Goes to JewelerSenior Jeweler Jay Wolff was named employee of the year.
MajorsMar 05, 2025
Neiman Marcus’ Dallas Flagship Store to Close, Confirms Saks GlobalThe 111-year-old store will close following a dispute among Saks Global, a landlord, and the City of Dallas over a small piece of land.
AuctionsMar 05, 2025
Sotheby's To Auction 51 ‘Alien’ WatchesThe upcoming “Area_51” watch sale is a collaboration with heist-out, featuring vintage and modern timepieces with futuristic designs.
MajorsMar 05, 2025
Jewelers of America Unveils 3-Year Strategic Plan The trade organization, which will mark 120 years of service next year, has a refined focus and a new mission statement.
Events & AwardsMar 05, 2025
92NY Accepting 2025 Jewelry Artist Residency ApplicationsThe application period is now open for established and emerging jewelers and metalsmiths to apply to the month-long residency program.
CrimeMar 04, 2025
4 Suspects Arrested in Fatal Armed Robbery of California Jewelry Store Uc Thí Vo, who co-owned Kim Tin Jewelry in Sacramento with her husband of 40 years, was killed during the November 2024 robbery.
CrimeMar 04, 2025
NYC Diamond Dealer Pleads Guilty to Lab-Grown Diamond SwapsManashe Sezanayev pleaded guilty to grand larceny and is expected to receive five years’ probation when he’s sentenced in May.
TrendsMar 04, 2025
Amanda’s Style File: Peaceful and Powerful AquamarineThe March birthstone pairs perfectly with hues of Mocha Mousse, Pantone’s Color of the Year for 2025.
ColumnistsMar 04, 2025
The Smart Lab: Using Online Events to Supercharge Sales Emmanuel Raheb shares strategies to prepare for, publicize, and engage the audience during events on platforms like TikTok and Zoom.
EditorsMar 03, 2025
Drop Necklaces, Archival Pieces Take Over at the 2025 OscarsFrom Doja Cat to Mikey Madison and Selena Gomez, many of this year’s Academy Awards attendees donned drop necklaces.
Policies & IssuesMar 03, 2025
Customs Indefinitely Postpones Requirement to Disclose Country of MiningOriginally slated to take effect in April, official U.S. Customs and Border Protection documents now show the implementation date as “TBD.”
SurveysMar 03, 2025
Consumer Confidence Fell in February Amid Concerns About the FutureThe recent jump in the prices of household staples, like eggs, and the potential impact of tariffs worried consumers.
Events & AwardsMar 03, 2025
AGA Now Accepting Applications for Its Gemological Education Scholarship The application period for the program is now open for aspiring gemologists around the world.
CollectionsFeb 28, 2025
Piece of the Week: Ironhorse Quillwork EarringsThe work of Indigenous designer Joe Big Mountain, these earrings are similar to the pair Lily Gladstone just wore to the SAG Awards.
AuctionsFeb 28, 2025
300-Year-Old Ring With Ties to Witch Trial Judge Up for Auction A metal detectorist uncovered the ring created in memory of Sir Richard Rainsford, who presided over some of England’s last witch trials.
