AuctionsDec 12, 2025
13.54-Carat Paraíba Tourmaline Sets Records at Christie’sSet in a Tiffany & Co. necklace, it sold for $4.2 million, the highest price and price per carat paid for a Paraíba tourmaline at auction.
GradingMay 22, 2019
GIA Spots Second Natural Diamond with Lab-Grown Layer
The stone is 0.64 carats and graded as a fancy grayish-greenish blue.
Gemological Institute of America researchers said the gray and blue components from the lab-grown layer of this diamond combined with the yellow from the natural substrate to create the color, fancy grayish-greenish blue. (Photo credit: Robison McMurtry)
Carlsbad, Calif.—GIA researchers recently spotted a second natural diamond with a lab-grown layer that added weight and improved the color, and warned that it could mean the trade will see more of these kind of composites.
According to an article by Troy Ardon and Garrett McElhenny in the spring 2019 edition of “Gems & Gemology,” the presence of both boron- and nitrogen-related defects—which are rarely seen together in natural diamonds—tipped them off there was something unusual about the stone.
The DiamondView fluorescence image of the diamond—a 0.64-carat fancy grayish-greenish blue cushion modified brilliant—showed a blue hue caused by the “cape” peak (nitrogen defect) and natural growth features.
The crown image, however, revealed a greenish-blue color common to boron-bearing diamonds and the dislocation patterns typically seen in diamonds grown using the chemical-vapor deposition (CVD) process.
In addition, a side view shows a distinct layer between the natural substrate and the CVD-grown portion of the stone. 
“These two distinct fluorescence patterns—the greenish-blue from the CVD layer and the darker blue from the naturally grown layer—prove that a layer of CVD synthetic diamond was grown on a natural substrate,” the article states.
A similar diamond, a 0.33-carat fancy blue that was also Type IIb with a CVD layer, was submitted to GIA in May 2017.
The CVD layer on this latest diamond is substantially thicker, 200 microns (approximately the thickness of two strands of human hairs) vs. 80 microns on the 0.33-carat diamond evaluated two years ago, and GIA noted that seeing a second example of this same type of composite could signal a new type of product entering the market.
The lab would not say if both diamonds came from the same client.
GIA also declined to comment on how the stones were submitted—as natural diamonds, or as natural/lab-grown composites—but did note that clients submitting goods are required to disclose all known treatments as well as whether a stone is natural or man-made.
To see more from the spring 2019 edition of “Gems & Gemology,” the Gemological Institute of America’s quarterly research journal, visit GIA.edu.
More on Grading
The Latest
MajorsDec 12, 2025
David Webb Reveals Ice-Cold Holiday Window DisplayThe jeweler’s “Deep Freeze” display showcases its iconic jewelry designs frozen in a vintage icebox.
CollectionsDec 12, 2025
Piece of the Week: Oscar Heyman’s Sphene RingTake luxury gifting to new heights this holiday season with the jeweler’s showstopping 12-carat sphene ring.
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.
Events & AwardsDec 12, 2025
IGI Jewelry Design Contest Now Accepting SubmissionsThis year's theme is “Unveiling the Depths of the Ocean.”
Weekly QuizDec 11, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
TrendsDec 11, 2025
Pinterest 2026 Trend Report: Brooches, Bold Gold, Cool BlueIn its annual report, Pinterest noted an increase in searches for brooches, heirloom jewelry, and ‘80s luxury.
IndependentsDec 11, 2025
Look Inside Day’s Jewelers’ Ninth StoreThe 111-year-old retailer celebrated the opening of its new location in Salem, New Hampshire, which is its third store in the state.
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.
MajorsDec 11, 2025
Americas Gold Releases New Gold Chain CatalogThe new catalog features its most popular chains as well as new styles.
AuctionsDec 10, 2025
Francis Ford Coppola’s Watch Sells for $10.8MThe filmmaker’s personal F.P. Journe “FFC” prototype was the star of Phillips’ recent record-setting watch auction in New York.
WatchesDec 10, 2025
There’s A New Rolex Boutique in MiamiThe new location in the Design District pays homage to Miami’s Art Deco heritage and its connection to the ocean.
SurveysDec 10, 2025
Consumer Confidence Drops in November Inflations, tariffs, and politics—including the government shutdown—were among consumers’ top concerns last month.
SourcingDec 10, 2025
NAJA Announces Details for 2026 ‘Ace It’ Winter Conference“Longtime favorite” presenters, as well as first-time speakers, will lead talks and workshops at the annual event in Tucson next year.
Events & AwardsDec 10, 2025
MJSA Names 2025 Responsible Design Challenge WinnerSilas Smith of Meridian Metalworks won the challenge with his pendant that blends Australian and American landscapes.
AuctionsDec 09, 2025
‘Desert Rose’ Diamond Sells for $8.8M in Abu DhabiThe sale of the 31.68-carat, sunset-hued stone was part of Sotheby’s first series of events and auctions in Abu Dhabi.
ColumnistsDec 09, 2025
Holiday Sales Happen in December, Most Decisions Don’tMost customers who walk into your store this month have made up their minds. Your job is to validate their choice, Emmanuel Raheb writes.
TrendsDec 09, 2025
‘Once Upon a Time,’ Guzema Debuted Its Holiday CollectionThe collection features characters and motifs from Ukrainian folklore, including an enchanted mirror and a magic egg.
TechnologyDec 09, 2025
Gemvision Releases Updated MatrixGoldMatrixGold 3.11, the newest version of the jewelry design program, offers more flexibility, precision, and creative control.
Events & AwardsDec 09, 2025
MJSA Showcase Pavilion Returning to JA New York The pavilion will be part of the 2026 JA New York Spring show, scheduled for March 15 to 17.
MajorsDec 08, 2025
Juell Kadet, a ‘Lifelong Pillar’ of Rogers & Hollands, Dies at 96Kadet, a 1994 National Jeweler Retailer Hall of Fame inductee, helped grow the family-owned retailer in the Chicago area and beyond.
TechnologyDec 08, 2025
You’ve Heard of Smart Watches and Rings; Meet Smart EarringsBilled as the world’s smallest wearable, Lumia Health’s new smart earrings have a health tracker subtly embedded in the back.
TrendsDec 08, 2025
Amanda’s Style File: Celebrating December’s BirthstonesDon’t let those with December birthdays feel blue. Help them celebrate their month with blue zircon, turquoise, and tanzanite.
CollectionsDec 05, 2025
Piece of the Week: Robinson Pelham’s ‘Tsar Star’ EarringsThe new pink sapphire version of the piece dances with its wearer in the brand’s “Icons After Dark” holiday campaign.
TrendsDec 05, 2025
Pantone’s Color of the Year for 2026 Is … WhiteA choice that’s generated a lot of commentary, Pantone says “Cloud Dancer” marks a fresh start and encourages relaxation and creativity.
MajorsDec 05, 2025
Stuller Releases ‘Wrapped in Wonder’ CampaignThe manufacturer’s holiday campaign features a gift guide filled with trending designs and jewelry that can be personalized.
CrimeDec 04, 2025
Man Arrested After Allegedly Swallowing Fabergé Egg PendantThe man was charged with theft, accused of ingesting the necklace while in a jewelry store in Auckland, New Zealand.
IndependentsDec 04, 2025
Step Inside JR Dunn Jewelers’ Giant New Store The Florida independent expanded its store from 8,000 to 14,000 square feet, fulfilling the vision of its late co-founder, Jim Dunn.
