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.
Editors' Picks
Sponsored by
More on Grading
The Latest
EditorsNov 06, 2026
The Spectrum Pieces I Can’t Stop Thinking AboutFrom a Betta fish brooch to a “dragon’s trove” of zircon eggs, here are seven pieces that’ve stuck with Associate Editor Lauren McLemore.
TrendsNov 06, 2026
Pat Pruitt’s DragonFly Earrings Take Flight on Election NightGroundbreaking New Mexico Governor-elect Deb Haaland wore the earrings, our Piece of the Week, when she declared victory on Tuesday.
MajorsNov 06, 2026
SNL’s Colin Jost Finds the Perfect Gift in Kay Jewelers’ Holiday AdJost goes on an epic journey, traversing rough seas and encountering a cyclops, to discover the perfect holiday gift.
Brought to you by
How Overnight Mountings’ Bridal Builder Makes Custom Engagement Ring Design Easier to SellWith customization becoming more expected in engagement ring shopping, the Bridal Builder makes the process tangible.
Supplier BulletinNov 05, 2026
Winning With GCAL 8X®: What’s Working at the CounterSponsored by GCAL by Sarine
Weekly QuizNov 05, 2026
This Week’s QuizTest your jewelry news knowledge by answering these questions.
SurveysNov 05, 2026
What Retailers Should Know About Holiday Shoppers This YearFrom shrinking budgets to AI elves, here are five takeaways from holiday reports by Bain, Adobe, Mastercard, NRF, and insights from YouGov.
CollectionsNov 05, 2026
Judi Powers, Russell Jones Unleash Joy With New CollaborationThe designers combined their talents for Little Pet Portraits, hand-painted miniatures of our best friends set in a piece of jewelry.
Brought to you by
A Diamond Is Forever Launches 2026 Holiday Campaign Championing Natural DiamondsA Diamond Is Forever's holiday campaign reimagines natural diamond icons for a new generation celebrating individuality.
FinancialsNov 05, 2026
Brilliant Earth Continued to Resonate With High-Income Shoppers in Q3Its non-bridal fine jewelry remains the star of the show, recently launching new collections inspired by Elizabeth Taylor and Jane Goodall.
MajorsNov 05, 2026
Ariana Grande Stars In Swarovski’s Holiday Campaign“Joy: The Swarovski Musical” features Ariana Grande as the leading lady in scenes inspired by classic musical montages.
CrimeNov 04, 2026
$250K+ in Undeclared Cartier Jewelry Seized at Philadelphia AirportA Pennsylvania woman failed to declare a ring and a bracelet, discarding the boxes and receipts to conceal the purchases, officials said.
FinancialsNov 04, 2026
Pandora’s Q3 Sales Up 7% Amid Focus on DesignNew collections and relevant marketing pushed the company forward, while Pandora’s lab-grown diamond sales continue to lag.
Events & AwardsNov 04, 2026
NYC Jewelry Week 2026 Is the Largest Edition YetThe citywide celebration, slated for Nov. 16-22, is set to host more than 175 events, including live jewelry-making demos.
MajorsNov 04, 2026
Bergdorf Goodman Names New PresidentLanessa Elrod, former president and CEO of Louis Vuitton Americas, has stepped into the role as the retailer celebrates 125 years.
AuctionsNov 03, 2026
Infinity Gauntlet Set With 170+ Carats of Colored Gemstones Up for AuctionA replica of one of the most powerful objects in the Marvel Cinematic Universe, the glove is heading to auction next month in Abu Dhabi.
IndependentsNov 03, 2026
Longtime Jewelry Marketer Arthur Klein Dies at 89Klein, who had his own marketing agency and worked for Gabriel & Co. and Trans American Diamond, is remembered as a kind man.
IndependentsNov 03, 2026
Zadok Jewelers Toasts To 50 Years With Diamond Bracelet GiveawayTo enter the giveaway, locals can purchase a featured beverage from one of eight participating restaurants in Houston and Austin, Texas.
Events & AwardsNov 03, 2026
David Yurman Gem Awards Grant Opens 2027 ApplicationsThe grant recipient will be awarded $50,000 as well as mentoring meetings with executives at David Yurman and other industry executives.
Events & AwardsNov 03, 2026
NAJA, Instappraise Name 2026 Scholarship WinnersThe winners include a non-NAJA member seeking training, a member beginning NAJA courses, and a member becoming a Certified Master Appraiser.
AuctionsNov 02, 2026
197-Carat ‘Romanov Sapphire’ Heads to Sotheby’s GenevaThe rare jewel, which has links to Russia’s Romanov dynasty, is estimated to fetch up to $2 million.
CrimeNov 02, 2026
Customs Seizes More Than 400 Fake Audemars Piguet WatchesIt is one of several seizures of counterfeit jewelry and watches by U.S. Customs and Border Protection officials in Louisville this year.
MajorsNov 02, 2026
Lawrence Bock, Caryl Capeci, Amanda Coleman-Phelps Join JA Board Jewelers of America announced the additions to its board of directors following its annual general meeting, held last week.
CollectionsNov 02, 2026
Olympian Kristi Yamaguchi, Heller Jewelers Expand ‘Always Dream’ CollectionThe jewelry collection supports Yamaguchi’s Always Dream foundation, which provides reading and educational resources to families in need.
Events & AwardsOct 30, 2026
Illuminating Carved Paraiba Pendant, Suite of Moonstones Wow at Spectrum AwardsSpectrum’s “Best of Show” honors went to a 101-carat Paraiba carved to look like Medusa that has a magnet-activated LED light.
TrendsOct 30, 2026
Edina Kiss’ Pendants Say ‘Eye’m Watching You’Our Halloween Pieces of the Week are four “Eye” pendants, each set with colorful gemstones.
MajorsOct 30, 2026
The RealReal Hires Former eBay Exec as New Chief Merchandising OfficerAlexis Hoopes expanded eBay’s “Authenticity Guarantee” program during her tenure.
WatchesOct 29, 2026
Bucherer Opens Rolex Boutique in Washington StateThe Rolex-owned retailer’s new 4,700-square-foot store’s façade honors the Pacific Northwest’s evergreen forests.
