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
CollectionsNov 19, 2025
Larkspur & Hawk Celebrates 25 Years With Helena Bonham Carter CampaignThe British actress and her daughter modeled pieces from the brand’s new “Palette” capsule for its “Once Upon a Time” holiday campaign.
TechnologyNov 19, 2025
Google Has a New Form for Reporting ‘Review Bombing’ Attacks Plus, the tech giant shares the steps retailers should take if they believe they’re a victim of a review extortion scam.
IndependentsNov 19, 2025
Houston Jeweler Keith Shaftel Retires, Next Generation Steps In Danny and Gaby Shaftel are now Shaftel Diamonds’ CEO and chief operating officer, respectively.
Brought to you by
Impacting Tomorrow TodayHow Jewelers of America’s 20 Under 40 are leading to ensure a brighter future for the jewelry industry.
TrendsNov 19, 2025
Midas Chain Releases 2025 Holiday Style GuideThe jewelry manufacturer’s seasonal offering features its new “Melodie” bangles, as well as mini stud earrings and layering pieces.
Weekly QuizNov 13, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
Events & AwardsNov 18, 2025
NYC Jewelry Week 2025: 12 Must-See EventsWith more than 140 activations taking place in New York City now through Nov. 23, these 12 events are can’t-miss moments.
MajorsNov 18, 2025
Lugano Diamonds Files for Bankruptcy, Looking for BuyerThe Chapter 11 filing follows the resignation of CEO Moti Ferder, who stepped down after an investigation into the company’s finances.
Brought to you by
Roseco Releases New Full-Line CatalogRoseco’s 704-page catalog showcases new lab-grown diamonds, findings, tools & more—available in print or interactive digital editions.
Events & AwardsNov 18, 2025
A Giant, Bejeweled Moldy Berry Is on Display in LAThe artwork is part of an exhibition featuring works by Kathleen Ryan, an artist known for her gemstone-studded rotting fruit sculptures.
SourcingNov 18, 2025
Another Diamond Company CEO Steps DownMark Wall, president and CEO of Canadian mining company Mountain Province Diamonds, will vacate his position next month.
CrimeNov 17, 2025
Police Searching for 2 Suspects in Murder of Father, Son Jewelers Faustino Alamo Dominguez and his son, 25-year-old Luis Angel Alamo, were gunned down following an armed robbery at their jewelry store.
MajorsNov 17, 2025
Look Inside Robbins Brothers Fine Jewelers’ New Pasadena FlagshipThe showroom is located in a historic 1920s building in the Playhouse District.
Policies & IssuesNov 14, 2025
U.S., Switzerland Reach Deal That Drops Tariff to 15%The Swiss government announced the deal, which cuts the tax on Swiss imports by more than half, on social media Friday morning.
AuctionsNov 14, 2025
Napoleon’s Diamond Brooch Blows Away Auction Estimates A buyer paid $4.4 million for the piece, which Napoleon wore on his hat for special occasions and left behind when he fled Waterloo.
FinancialsNov 14, 2025
Richemont’s Q2 Jewelry Sales Up 12%Plus, how tariffs and the rising price of gold are affecting its watch and jewelry brands.
CollectionsNov 14, 2025
Piece of the Week: Silvia Furmanovich’s ‘Butterflies in Flight’ Jewelry BoxFurmanovich designed the box to hold Mellerio’s “Color Queen,” a high jewelry collection consisting of 10 rings.
Events & AwardsNov 14, 2025
JCK Names New Event DirectorJennifer Hopf, who has been with JCK since 2022, will lead the execution of the long-running jewelry trade show.
IndependentsNov 13, 2025
127-Year-Old New Orleans Jeweler to CloseAdler’s Jewelry is set to close its two stores as 82-year-old owner Coleman E. Adler II retires.
IndependentsNov 13, 2025
Green Lake Jewelry Works to Move to New Seattle StudioFounder Jim Tuttle shared how a dedication to craftsmanship and meaningful custom jewelry fueled the retailer’s double-digit growth.
MajorsNov 13, 2025
Vahan Jewelry Founder Leon ‘Sacha’ Der Calousdian Dies at 85The third-generation jeweler is remembered as a passionate creative with a love of art, traveling and sailboat racing.
CrimeNov 12, 2025
Father, Son Jewelers in Chicago Victims in Double Homicide JSA and Cook County Crime Stoppers are both offering rewards for information leading to the arrest of the suspect or suspects involved.
AuctionsNov 12, 2025
‘Mellon Blue’ Diamond Sells for $7M Less Than It Did a Decade AgoA buyer paid $25.6 million for the diamond at Christie’s on Tuesday. In 2014, Sotheby’s sold the same stone for $32.6 million.
AuctionsNov 12, 2025
Historic Rolex Oyster Fetches $1.7M at Sotheby’sMercedes Gleitze famously wore the watch in her 1927 swim across the English Channel, a pivotal credibility moment for the watchmaker.
MajorsNov 10, 2025
Jewelers Focus on Love, Joy In 2025 Holiday Campaigns Tiffany & Co., David Yurman, and Pandora have launched holiday campaigns depicting their jewelry as symbols of affection and happiness.
SurveysNov 10, 2025
5 Things Retailers Should Know About Holiday Shoppers This YearThe National Retail Federation is bullish on the holidays, forecasting retail sales to exceed $1 trillion this year.
AuctionsNov 10, 2025
300+ Colored Diamonds Up for Auction at Christie’sLate collector Eddy Elzas assembled “The Rainbow Collection,” which is offered as a single lot and estimated to fetch up to $3 million.
EditorsNov 07, 2025
Piece of the Week: An MVP’s Sapphire Tennis Necklace At the 2025 World Series, the Los Angeles Dodgers’ Yoshinobu Yamamoto sported a custom necklace made by California retailer Happy Jewelers.
