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
CrimeAug 04, 2026
Crew of Thieves Break Into Indiana Jeweler’s HomeFour men were charged in connection with the break-in and accused of stealing $365,000 in cash, jewelry, and designer goods.
MajorsAug 04, 2026
Pandora Hires Former Signet Board Member to Lead North American MarketAndré Branch has more than 25 years of experience with various brands, most recently serving as CEO of Ariana Grande’s cosmetics company.
MajorsAug 04, 2026
Sasha Primak Acquires GemlokNew York-based atelier Gemlok is best known for creating the innovative “bridge” setting that became popular in the bridal market.
Brought to you by
Why More Jewelry Retailers Are Hosting Turnkey Estate Buying EventsRetailers are seeking new ways to attract customers, increase traffic, and create revenue – Estate buying events are a popular solution.
CollectionsAug 04, 2026
Musician Carlos Santana Launches Jewelry BrandSantana Now's debut collection, “Unidad,” features symbolic motifs as well as pieces of wood from the Woodstock stage.
Weekly QuizJul 30, 2026
This Week’s QuizTest your jewelry news knowledge by answering these questions.
CrimeAug 03, 2026
Florida Man Gets 15 Years in Trio of Jewelry Store RobberiesThe 50-year-old man pleaded guilty earlier this year to robbing two jewelry stores and a pawn shop of more than $700,000 in merchandise.
WatchesAug 03, 2026
Citizen's New Spider-Man Watch Is a Collector’s DreamThe watch’s dial features an original design by Marvel comics illustrator Adam Kubert.
Brought to you by
Wedding Band Trends 2026: Personalization Takes Center StageColored gemstones, artisan finishes, mixed metals, and meaningful details are shaping demand in bridal jewelry.
CollectionsAug 03, 2026
Chatham Releases First Men’s CollectionThe new collection of lab-grown diamond and colored gemstone jewelry provides a “fresh perspective” on the category, Chatham said.
TrendsAug 03, 2026
Amanda’s Style File: Spinel vs. Peridot While some August babies are team peridot, the month's time-honored birthstone, others are team spinel, the newer alternative.
TrendsJul 31, 2026
These Pieces of the Week Are Sweet Edina Kiss’ “Popsicle” pendant and Karina Choudhrie’s “Ice Cream” charm satisfy that summer craving for a sweet piece of jewelry.
MajorsJul 31, 2026
Macy’s Iconic Red Shopping Bag Sign Torn DownThe massive billboard has been in the same spot on the department store’s Herald Square flagship store for decades.
SourcingJul 31, 2026
Gemfields’ H1 Revenue Jumps 72%The miner’s ruby and emerald auctions brought in a combined $102.9 million.
SourcingJul 30, 2026
De Beers Sale in ‘Final, Most Challenging’ Phase, Anglo CEO SaysThe goal is for the De Beers sale to be finished by the second half of 2026, with the subsequent approvals process expected to take a year.
Policies & IssuesJul 30, 2026
JA Heads Back to Washington as New Wave of Tariffs Takes Effect David Bonaparte, along with Tim Haake and Ronnie VanderLinden, continue to lobby for tariff exemptions for diamonds, gemstones, and pearls.
SurveysJul 30, 2026
Consumer Confidence Slips in JulySurvey respondents were concerned about the rising prices of food and groceries as well as unemployment.
Events & AwardsJul 30, 2026
Vicenzaoro Releases 2026 Education LineupThe trade show, slated for Sept. 4-8 in Vicenza, Italy, will feature sessions on trends, AI, gemology, and manufacturing.
Events & AwardsJul 30, 2026
Hillsborough Show Moves to New Location for 2026The public shopping event featuring art, jewelry, watches, and rare collectibles, will take place in Santa Clara, California, this fall.
EditorsJul 29, 2026
Q&A: The Past and Future of Angola’s Diamond Industry Endiama Commercial Director Elton Escrivão knows people have a lot of misperceptions about Angola. He wants to change that.
MajorsJul 29, 2026
Kevin Reilly Retires After 39 Years in the Jewelry Industry Reilly has been with PGI USA for the last 20 years, leading partnership development and professional education.
FinancialsJul 29, 2026
Kering’s H1 Jewelry Sales Up 14%Boucheron reached record sales while Pomellato found success in its signature collections.
Events & AwardsJul 29, 2026
Lauren Harwell Godfrey Designs a Flag for ArkansasShe was one of more than 120 American designers who created flags for the “United Flags of Fashion” project led by CFDA and Vogue.
ColumnistsJul 28, 2026
Peter Smith: Why Your Job Postings May Be Working Against You Smith reveals the method The Retail Smiths use to help retailers and vendors write better job postings.
FinancialsJul 28, 2026
Tiffany & Co., Bulgari Lead the Way for LVMH in H1LVMH’s jewelry and watch brands outperformed the company’s other divisions in an environment the company described as “disrupted.”
CollectionsJul 28, 2026
Lionheart’s New Collection Unites Spiritual Iconography“Sacred Heart” features symbols like crosses, angel wings, the Star of David, and the evil eye as a representation of coexistence.
Events & AwardsJul 28, 2026
The Edge Funding 2 Scholarships Via 24 Karat Club SEUS The scholarships will go to early-career professionals looking to study gemology, bench work and jewelry design, or store operations.
SurveysJul 27, 2026
Jewelry Leads Luxury Market Amid Stabilization, Bain SaysBain & Company delved into the trends shaping the luxury market, the impact of AI, and more in its recent study.
