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
CollectionsMay 29, 2026
Cultus Artem’s Necklace Is the Oasis in Las Vegas’ DesertThe “River of Heaven” necklace, our Piece of the Week debuting at Couture, combines 26 salt and pepper diamonds spaced by Tahitian pearls.
IndependentsMay 29, 2026
Meet the 2026 Retailer Hall of Fame InducteesThis year’s inductees include second-, third-, and fourth-generation jewelers.
Events & AwardsMay 28, 2026
JCK Announces Jesse Itzler as 2026 Keynote SpeakerThe author, speaker, and entrepreneur will give his presentation, “Spiritual Billionaire,” on Saturday morning.
Brought to you by
All Eyes on Gold Prices. Alternatives to Look For. And What to BEWARE of in VegasAs gold prices rise, today’s retailers are looking for alternatives at prices that will appeal to wider audiences.
Events & AwardsMay 28, 2026
JCK Rocks To Ride With NellyThree-time Grammy award-winning artist Nelly is set to perform at the annual event at Tao Beach on Sunday night.
Weekly QuizMay 28, 2026
This Week’s QuizTest your jewelry news knowledge by answering these questions.
MajorsMay 28, 2026
Signet Jewelers to Buy The Clear Cut Signet will integrate the online-only, natural diamond-focused jeweler into Blue Nile, which it wants to position as a higher-end retailer.
CollectionsMay 28, 2026
Meet The 17 Newcomers to Couture’s Design AtelierThese up-and-coming jewelry brands are bringing their distinct aesthetic and unique point-of-view to the Design Atelier for the first time.
Brought to you by
How Modern Training Is Becoming a Competitive Advantage for Jewelry RetailersWith the trade and customer trust in mind, GIA® developed NextGem™ – on-demand training designed specifically for retail.
Events & AwardsMay 27, 2026
5 Security Tips for Las Vegas Jewelry Market Week 2026This year, it’s what could happen outside of show hours that worries JSA Executive Vice President Scott Guginsky.
ColumnistsMay 27, 2026
What Jewelers Can Learn From Luxury Fashion’s Digital PlaybookHigh-end fashion houses know how to emotionally connect with customers online. Retail jewelers should take note, Emmanuel Raheb writes.
Events & AwardsMay 27, 2026
Couture’s ‘The Iridescence’ Will Showcase 7 Emerging Jewelry DesignersThe designers are the third cohort of mentees from the show’s Belonging @ Couture mentorship program.
ColumnistsMay 26, 2026
The Key Mindset for Better Trade Show BuyingBuying discipline at trade shows starts with clarity about your inventory levels, Smith writes.
Events & AwardsMay 26, 2026
12 JCK Talks Sessions to Add to Your Las Vegas ScheduleThe trade show’s education series returns, with sessions on retail trends, AI, watches, marketing, corporate responsibility, and more.
Events & AwardsMay 26, 2026
CBG Brings Its Curated Designer Project to Las Vegas ShowThe Curated Designer Project has expanded to highlight eight independent jewelry designers during CBG’s Las Vegas show.
TrendsMay 26, 2026
Amanda’s Style File: A Cooldown Is ComingBring a cool tone to your summer jewelry with these white metal pieces.
Events & AwardsMay 22, 2026
Instore Buys JA New York ShowThe deal closed this week, which means Instore will produce the JA NY show slated to take place this fall.
FinancialsMay 22, 2026
Richemont’s Jewelry Brands Lead the Charge in Q4The company’s jewelry sales were up in Q4 and the fiscal year, with Richemont raising prices in part because of the cost of gold.
CollectionsMay 22, 2026
Leigh Maxwell Celebrates 5 Years at Couture With ‘Bauble’ CollectionThe “Bauble” capsule collection of colorful one-of-a-kinds includes our Piece of the Week, the “Bauble” earrings, featuring rose zircon.
MajorsMay 22, 2026
Stuller’s New Packaging, Display Catalog Is Out The updated catalog has a newly dedicated section for gift wrapping.
PodcastsMay 21, 2026
Episode 5: Sotheby’s Frank Everett Puts the Auction Market in PerspectiveEverett covers colored stones’ surging popularity, the mellow return of the “Mellon Blue,” and his “The Devil Wears Prada” doppelgänger.
IndependentsMay 21, 2026
Springer’s Jewelers’ New Flagship Will Serve Next-Gen Luxury ShoppersFourth-generation CEO Lilly Mullen wants to emphasize experience, connection, and personalized service.
Events & AwardsMay 21, 2026
JA Announces Nina Pugliese Memorial ScholarshipThe new award, created in partnership with Henne Jewelers, honors the late designer’s legacy through supporting jewelry education.
SourcingMay 21, 2026
Botswana, Angola Join WFDBThe addition of the diamond-producing countries as nation affiliated members broadens the federation’s global representation, WFDB said.
CrimeMay 20, 2026
NYPD Warns of Jewelry Swap Scams Targeting SeniorsThe NYPD is warning elderly New Yorkers to keep their jewelry hidden when walking outside to avoid being a target.
IndependentsMay 20, 2026
Adornment & Theory’s New Store Feels Like Home Designer Viviana Langhoff has realized her dream of owning a space for her Chicago jewelry store that looks and feels like her brand.
Events & AwardsMay 20, 2026
Here Is Couture’s 2026 Education Lineup The sessions will run from Friday, May 29, to Sunday, May 31, with one being a live taping of an episode of Couture’s podcast.
Lab-GrownMay 20, 2026
Savannah Friedkin Jewelry Names New CEOFormer Stephanie Gottlieb Fine Jewelry executive Morgan P. Richardson is joining the lab-grown diamond jewelry brand.
