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
FinancialsDec 02, 2025
Signet Jewelers’ Q3 Sales Up Amid Continued Focus on Lower Price PointsThe retailer offered more fashion jewelry priced under $1,000, including lab-grown diamond and men’s jewelry.
CollectionsDec 02, 2025
Briony Raymond Introduces First FragranceThe eau de parfum is held in a fluted glass bottle that mirrors the decor of the brand’s atelier, and its cap is a nod to its “Sloan” ring.
SourcingDec 02, 2025
Petra Diamonds Elevates Interim CEOs to Permanent StatusVivek Gadodia and Juan Kemp, who’ve been serving as interim co-CEOs since February, will continue to lead the diamond mining company.
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.
MajorsDec 02, 2025
Lee Krombholz Takes Over as Chair of MJSA Education FoundationIn addition, a slate of new officers and trustees were appointed to the board.
Weekly QuizNov 20, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
IndependentsDec 02, 2025
RJO Welcomes Its 1,200th Retail MemberWitt’s Jewelry in Wayne, Nebraska, is the organization’s new milestone member.
SourcingDec 02, 2025
Brendan Laurs Honored With 2025 Bonanno AwardLaurs is the editor-in-chief of Gem-A’s The Journal of Gemmology and an expert on the formation of colored gemstone deposits.
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.
CrimeDec 01, 2025
Fourth Man Charged in Louvre Jewelry HeistThe man, who has a criminal history, is suspected of being the fourth member of the four-man crew that carried out the heist.
AuctionsDec 01, 2025
Christie’s Presents ‘Splendor & Style’ CollectionThe single-owner collection includes one of the largest offerings of Verdura jewels ever to appear at auction, said Christie’s.
IndependentsDec 01, 2025
Lustig Jewelers’ New Owner Is a Fellow Chicago JewelerMichael Helfer has taken the reins, bringing together two historic Chicago jewelry names.
MajorsDec 01, 2025
PGI Debuts Platinum-Filled Holiday Gift GuideThe guide features all-new platinum designs for the holiday season by brands like Harwell Godfrey, Ritani, and Suna.
FinancialsNov 26, 2025
Movado CEO Talks Tariffs, Growing Interest in Accessible Luxury WatchesDuring its Q3 call, CEO Efraim Grinberg discussed the deal to lower tariffs on Swiss-made watches, watch market trends, and more.
TrendsNov 26, 2025
Piece of the Week: Rosior’s Pumpkin RingRosior’s high jewelry cocktail ring with orange sapphires and green diamonds is the perfect Thanksgiving accessory.
IndependentsNov 26, 2025
Greenwich St. Jewelers Launches Colorful Holiday CampaignThe “Embrace Your True Colors” campaign features jewels with a vibrant color palette and poetry by Grammy-nominated artist Aja Monet.
MajorsNov 26, 2025
Serafino Consoli Names New VP of Sales, Brand Development for the AmericasLuxury veteran Alejandro Cuellar has stepped into the role at the Italian fine jewelry brand.
Events & AwardsNov 26, 2025
Grandview Klein Presents 4 Scholarships in NamibiaThe company gave awards to four students at the Namibia University of Science & Technology, including one who is a Grandview Klein employee.
IndependentsNov 25, 2025
Pearl Stringer Margaret Hoisik DiesShe is remembered as an artist who loved her craft and was devoted to her faith, her friends, and her family.
SourcingNov 25, 2025
Finestar Opens Diamond Manufacturing Facility in JohannesburgIt joins the company’s other manufacturing facilities globally, including in India, Botswana, and Namibia.
TrendsNov 25, 2025
Amanda’s Style File: Polka DotsThe polka dot pattern transcends time and has re-emerged as a trend in jewelry through round-shaped gemstones.
CrimeNov 25, 2025
Former Arizona AG Official Charged With Trafficking Stolen JewelryVanessa Hickman, 49, allegedly sold a diamond bracelet that was mistakenly sent to her home.
Events & AwardsNov 25, 2025
GIA Awards Susan Jacques With Its Highest HonorGIA’s former president and CEO was presented with the Richard T. Liddicoat Award for Distinguished Achievement.
Recorded WebinarsNov 24, 2025
Watch: Top Tips for Social Media EtiquetteSocial media experts spoke about protecting brand reputation through behaving mindfully online.
WatchesNov 24, 2025
Breitling Reveals Plans for Gallet, Universal GenèveIn 2026, the three will come together as “House of Brands,” with Gallet sold in Breitling stores and Universal Genève sold separately.
CollectionsNov 24, 2025
Muse Debuts a Wicked 'Have a Heart x Cynthia Erivo' SequelThe second drop, which includes more Elphaba-inspired pieces from additional designers, will continue to benefit nonprofit Dreams of Hope.
IndependentsNov 24, 2025
J.R. Dunn Jewelers Names New PresidentSecond-generation jeweler Sean Dunn has taken on the role.
MajorsNov 21, 2025
Natural Diamond Council Names New CEOAmber Pepper’s main focus will be on digital innovation and engaging younger consumers.
