GradingNov 17, 2022
GIA Labs Report Receiving 2 Moissanites Submitted as Diamonds GradingDec 14, 2022
GIA Sees ‘Unusual’ Color Change in Sapphires During Stability Testing
Some sapphires gain orange or yellow coloration when exposed to incandescent light, according to a recent lab note.
A 3.54-carat padparadscha sapphire submitted to the GIA laboratory underwent a color stability test, during which time its orange color increased. If left in the dark for a while, the color could become less orange or straight pink, GIA said. The lab said this stone would be called a padparadscha sapphire because the pink-orange color seen after the stability test (far right) fits that range. (Photo credit: Diego Sanchez)
Carlsbad, Calif.—In color stability testing of sapphires, the Gemological Institute of America has noticed an “unusual” color change, according to a recent Lab Note.
GIA has performed color stability tests on some sapphires for decades but recently started using the test to identify pink sapphires that have a temporary change of color.
According to the Lab Note written by Aaron Palke, Shane McClure, and Nathan Renfro, some pink sapphires, when exposed to UV light, temporarily change into the orangey pink to pinkish orange hue range of padparadscha sapphires or can become even more orange in appearance.
The change can also happen when these same sapphires are exposed to sunlight, although it takes longer, GIA noted.
The unstable orange component will fade away with a few hours of exposure to “intense incandescent illumination,” GIA said, and return the color to pink.
In these cases, GIA will only call the sapphire “padparadscha” if the color fits within the range after the stability test.
But, recently, GIA has also observed sapphires reacting to the color stability test by gaining orange or yellow coloration after being exposed to incandescent light; some pink sapphires shift to a padparadscha color or pure orange, and the saturation of pale yellow sapphires can increase.
If these sapphires were to be stored in the dark for a while, they would fade to the ground state, which is typically purplish pink, pink, or pale yellow, GIA reported.
Further exposure to light containing UV, including sunlight, would lead to the sapphire again showing the orange or yellow color.
Importantly, GIA said the gaining of color during the stability test has been observed in all the color-unstable sapphires used in its research project after they faded to their ground state under intense LED light or when left in the dark.
It added: “While this is not part of GIA’s normal testing procedures for color-unstable sapphires, it is expected that any color-unstable sapphire could behave similarly and gain color during the stability test to some extent, depending on its initial color (e.g., if left in the dark for extended time).”
It also noted that color instability might not always be identified if the starting color is close to the color created when it’s exposed to incandescent light.
Its results, it said, bring up the questions of how gem labs should determine the color of sapphires that change after UV light exposure and which color should be used to describe them.
GIA said the colors it saw after performing the tests were very similar to what it observed after the stones were exposed to daylight, which is how they would appear if they were set and worn often.
Because of this, and in an effort to create a “consistent and easily accessible standard,” the authors said GIA will indicate on its colored stone reports the color after the incandescent light stability test is performed.
This will be the case no matter if a sapphire loses or gains yellow or orange color during the test, GIA added.
Full results of its research in the area will be published in its Gems & Gemology journal soon.
To see full issues and articles, visit GIA.edu.
More on Grading
The Latest
SurveysOct 16, 2026
How Inflation, Gas Prices Will Affect Holiday Sales The NRF is expecting holiday sales to increase this year, but consumers and retailers alike are facing Grinch-like headwinds.
CollectionsOct 16, 2026
Christina Puchi’s Earrings Hold the UniverseOur Piece of the Week gathers the planets, represented by a variety of colored gemstones, in a pair of 14-karat yellow gold earrings.
IndependentsOct 16, 2026
Reeds Jewelers Expands, Relocates FlagshipThe New York-based jeweler is moving its Amherst flagship store to a larger location in nearby Snyder.
Brought to you by
Meet Gemology’s Next Generation Microscope: GIA® Gemolite® NXT Professional EditionExperience gemstones with greater precision and comfort than ever before.
MajorsOct 16, 2026
Katy Chen Appointed Executive Vice President of Graff USA Chen, who worked at Cartier and Tiffany & Co., will lead retail sales and operations for the luxury jeweler’s 11 U.S. stores.
Weekly QuizOct 15, 2026
This Week’s QuizTest your jewelry news knowledge by answering these questions.
IndependentsOct 15, 2026
Retailer Hall of Fame 2026: Amy and Elise Greenberg For 40 years, sisters Amy and Elise Greenberg have helmed their 126-year-old family business, leading with appreciation and integrity.
ColumnistsOct 15, 2026
Peter Smith: What Is the Culture REP?It’s a term Smith coined and felt compelled to share following a bad experience with an aborted flight and an unfeeling flight attendant.
Brought to you by
Your Piece Could Be the One Editors Talk AboutSubmit your pieces for a chance to win in this year's competition.
WatchesOct 15, 2026
Stephanie Gottlieb’s New Movado Watches Are Made for Your Wrist StackMovado teamed up with the New York-based fine jewelry designer on a new collection of Movado Museum Velura watches.
SourcingOct 15, 2026
Signet Jewelers, Richemont May Join Bidder for De Beers, Report SaysThe two companies are reportedly in talks to join the Global Diamond Consortium, led by former De Beers CEO Gareth Penny, as per Bloomberg.
CollectionsOct 15, 2026
Wolf x Marla Aaron's New Jewelry Box Is for Some (Not All) of Your ThingsThe “Some of the Things” box follows the two larger “Everything” box designs with the look and function of antique sewing and toolboxes.
IndependentsOct 14, 2026
Retailer Hall of Fame 2026: Coleman and Mitchell ClarkFourth-generation jewelers Coleman and Mitchell Clark exemplify the best qualities of their predecessors: humility, modesty, and confidence.
SourcingOct 14, 2026
Manuel Marcial de Gomar, ‘The Emerald Whisperer,’ Dies at 90The gem hunter, whose 70-year career was defined by adventure and exploration, is remembered for his steadfast faith and sense of wonder.
FinancialsOct 14, 2026
LVMH’s Jewelry Brands Turn in ‘Very Good’ Performance in Q3 Tiffany & Co. continued its full-scale store renovation project while Bulgari’s high jewelry collection generated “record-breaking revenue.”
Events & AwardsOct 14, 2026
Chicago Responsible Jewelry Conference Releases 2026 ProgramThis year’s sessions feature leading voices from human rights, legal, and conservation organizations.
MajorsOct 13, 2026
David Webb Owner Purchases Lugano JewelryThe high-end jewelry retailer was sold to private investment firm Middle West Partners and a group of longtime clients.
Lab-GrownOct 13, 2026
Stephanie Gottlieb Takes Lab-Grown Diamond Collection WholesaleThe jewelry designer has partnered with Sofer Jewelry to distribute her 85-piece lab-grown diamond collection.
IndependentsOct 13, 2026
Retailer Hall of Fame 2026: Sean DunnDunn, this year’s Single-Store Independent inductee, is passionate about innovation and telling the story of natural diamonds.
AuctionsOct 13, 2026
Christie's Geneva To Auction 'Bulgari Pink' DiamondThe 24-carat fancy intense pink diamond ring could fetch up to $18 million at the November sale.
IndependentsOct 13, 2026
Greenwich St. Jewelers’ New Candle Smells Like HomeThe “Island Jewel” candle honors New York City and Puerto Rico and raises money for the island’s water relief efforts.
TechnologyOct 13, 2026
GemFind Is a New JA Member Benefit Partner The partnership will give JA members access to preferred pricing, exclusive benefits, technology solutions, education, and resources.
SurveysOct 09, 2026
These Will Be the 10 Busiest Days for In-Store Shopping This Holiday SeasonStores should expect to see the most customers on Nov. 27, and Christmas week is expected to be hectic too, as Dec. 25 falls on a Friday.
CollectionsOct 09, 2026
Elisa Solomon Collabs With Serendipity 3 on ‘Frozen Hot Chocolate’ CharmThe charm, our Piece of the Week, features brown diamond frozen hot chocolate topped with white diamond whipped cream and a ruby straw.
AuctionsOct 09, 2026
8-Carat Blue Diamond Goes Unsold at UK Jewelry Auction The top lot of Elmwood’s recent fine jewelry sale in London was a 1.84-carat, D color Tiffany & Co. solitaire diamond ring.
WatchesOct 09, 2026
Movado to Sell Majority Stake in Ebel for $66.5MThe watch company agreed to sell a 95 percent interest to a group comprised of F.P. Journe, Chanel, and Swiss watch exec Pierre Jacques.
Policies & IssuesOct 08, 2026
Third Wave of IEEPA Tariff Refunds Begins This round of tariff refunds is for importers that have sued over IEEPA tariffs in the Court of International Trade and won.
CollectionsOct 08, 2026
Brent Neale’s New Collection Goes ‘Back to Basics’It revisits the brand’s most requested silhouettes, from "Pillow"-set necklaces and bracelets to "Signature"-set rings and earrings.
