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
MajorsOct 25, 2024
This New Bulgari Boutique Is on a YachtStarboard Luxury is bringing the Italian brand aboard The Ritz-Carlton Yacht Collection’s newest yacht.
CollectionsOct 25, 2024
Piece of the Week: A Haunting Piece of Mourning Jewelry The pendant, circa the late 1700s, likely was commissioned to remember a loved one who died young.
MajorsOct 25, 2024
Artistry Releases Its 2025 CatalogIt features the brand’s products in the precious color, semi-precious color, pearl, diamond, gold, and sterling silver categories.
Brought to you by
Navigating Cybersecurity: Essential Guidance for JewelersFrom protecting customer data to safeguarding inventory records, it's crucial to learn how to tackle cybersecurity challenges.
EditorsOct 24, 2024
From a Witch to Wednesday: The Best Jewelry to Wear With Your Halloween CostumeFor her annual Halloween story, Associate Editor Lenore Fedow pairs fine jewelry with classic and contemporary Halloween costumes.
Weekly QuizOct 24, 2024
This Week’s QuizTest your jewelry news knowledge by answering these questions.
FinancialsOct 24, 2024
Kering’s Jewelry Brands ‘More Resilient’ Than Other Luxury Goods in Q3 Sales fell 15 percent for the luxury conglomerate in the third quarter, led by a 26 percent drop in sales for flagship brand Gucci.
Events & AwardsOct 24, 2024
JA New York Fall Show Announces Education LineupThe education offerings include a diamond cutting demonstration, a session with JVC President Sara Yood, and a seminar on AI.
Brought to you by
Enhance Your Expertise with IGI’s In-Person Courses in NYCThis fall, sharpen your skills in jewelry grading, quality control and diamond assessment.
MajorsOct 24, 2024
Phillip Gavriel Releases 2024-2025 Catalog The book features new styles and revived favorites.
SourcingOct 23, 2024
De Beers, Signet Lean Into Finding ‘The One’ in New Natural Diamond Campaign Aimed at a generation that emphasizes self-care and mental health, “Worth the Wait” breaks new ground in the world of diamond advertising.
EditorsOct 23, 2024
The Modern Bride’s Approach to Wedding-Day JewelryEditor Lauren McLemore immersed herself in New York Bridal Fashion Week to better understand the role fine jewelry plays on the big day.
Lab-GrownOct 23, 2024
Q&A: Constance Polamalu on Selling Natural and Lab-Grown DiamondsThe jeweler shared her change of heart on lab-grown diamonds and why she keeps them separate from natural diamonds in her business ventures.
IndependentsOct 23, 2024
Jade Trau Sails OverseasThe New York-based brand is expanding outside of the U.S., with a pop-up shop in London and plans to distribute internationally.
CollectionsOct 23, 2024
See Scott West Jewelry’s ‘Kryptonite’ and ‘Joker’ RingsThey’re available through a retailer that sells luxury products inspired by the lifestyle of Batman’s billionaire civilian persona.
WatchesOct 23, 2024
How to Get a Timex Watch for $1The watchmaker is selling 1,000 “Waterbury” watches for $1 each in celebration of its 170th anniversary.
SourcingOct 23, 2024
GemFair Buys 10,000th DiamondLaunched by De Beers in 2018, the program aims to develop a responsible sourcing model for the artisanal/small-scale diamond mining sector.
CollectionsOct 23, 2024
Robinson Pelham Releases New Jewels Just in Time for the Holidays The new “Ouche” collection brings sculptural designs to the brand, while the expanded “Daystar” collection brings a rainbow of colors.
AuctionsOct 22, 2024
Phillips to Auction Rare 18-Carat Burmese Ruby The auction house said the gemstone could fetch up to $5.5 million at next month’s sale.
ColumnistsOct 22, 2024
The Smart Lab: Tips for Preparing for Your Best Q4 YetFrom prioritizing the customer experience to optimizing inventory, columnist Emmanuel Raheb shares the keys to a successful holiday season.
Events & AwardsOct 22, 2024
WJA Foundation Names First Winner of Hedda Schupak Scholarship Journalist Priya Raj plans to use the scholarship funds to further her media qualifications and amplify marginalized communities.
MajorsOct 22, 2024
WNBA Champions New York Liberty Take Home Tiffany & Co. TrophyIt marks the first championship win in the team’s 28-year history.
IndependentsOct 22, 2024
Sissy’s Log Cabin To Open Seventh StoreThe Arkansas-based jeweler’s first store in the state’s northwest region is set to open next year.
SourcingOct 21, 2024
De Beers to List Single Country of Origin for Some of Its Diamonds It will start with rough diamonds that are larger than 1.25 carats and later expand to rough diamonds that are above 1 carat.
CollectionsOct 21, 2024
Pandora Turns Things Upside Down in New ‘Stranger Things’ CollectionThe capsule collection is inspired by friendship and connection, with a nod to ‘80s fashion.
AuctionsOct 18, 2024
Piece of the Week: Babe Paley’s Clip-Brooch NecklaceThe New York socialite’s elegant, transformable piece from the 1960s is headed to auction later this month.
Recorded WebinarsOct 18, 2024
Watch: 2 Experts on the Challenges of Appraising Lab-Grown DiamondsTexas jeweler Susan Eisen and NAJA’s Gail Brett Levine discuss how lab-grown diamonds have altered the landscape for jewelry appraisers.
CrimeOct 18, 2024
The End of an Era: John Kennedy Reflects On 32 Years at JSA On the verge of retirement, Kennedy recounts the most stressful stretch of his time at JSA and reveals what he’ll miss about the industry.
