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
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.
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.
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.
Weekly QuizNov 20, 2025
This Week’s QuizTest your jewelry news knowledge by answering these questions.
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.
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.
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.
SourcingNov 21, 2025
De Beers’ Branded, Traceable Diamonds Roll Out to 19 Retailers Called “Origin by De Beers Group,” the loose, polished diamonds are being sold in a total of 30 stores in the United States and Canada.
CollectionsNov 21, 2025
Piece of the Week: Melissa Kaye’s ‘Rocky Infinity’ NecklaceThe lariat necklace features a 4.88-carat oval-cut Zambian emerald in 18-karat yellow gold.
AuctionsNov 20, 2025
Vanderbilt Jewels Shine at Phillips Sale, Pink Diamond WithdrawnA 43-carat sapphire brooch from the Vanderbilt collection was the top lot of the Geneva sale.
CollectionsNov 20, 2025
Rebecca Rau Jewels Debuts With ‘Then & Now’ CollectionRau is a fourth-generation art and antique dealer from M.S. Rau gallery whose first jewelry collection merges artifacts with modern design.
Policies & IssuesNov 20, 2025
RJC Names New Executive DirectorFormer De Beers sustainability leader Purvi Shah will take over the role in February 2026.
WatchesNov 20, 2025
LVMH Takes Minority Stake in Citizen Group-Owned Movement Maker La Joux-Perret is based in La Chaux-de-Fonds, Switzerland, and makes solar quartz as well as mechanical watch movements.
CollectionsNov 19, 2025
Larkspur & Hawk Celebrates 25 Years With Helena Bonham Carter CampaignThe British actress and her daughter modeled pieces from the brand’s new “Palette” capsule for its “Once Upon a Time” holiday campaign.
TechnologyNov 19, 2025
Google Has a New Form for Reporting ‘Review Bombing’ Attacks Plus, the tech giant shares the steps retailers should take if they believe they’re a victim of a review extortion scam.
IndependentsNov 19, 2025
Houston Jeweler Keith Shaftel Retires, Next Generation Steps In Danny and Gaby Shaftel are now Shaftel Diamonds’ CEO and chief operating officer, respectively.
TrendsNov 19, 2025
Midas Chain Releases 2025 Holiday Style GuideThe jewelry manufacturer’s seasonal offering features its new “Melodie” bangles, as well as mini stud earrings and layering pieces.
Events & AwardsNov 18, 2025
NYC Jewelry Week 2025: 12 Must-See EventsWith more than 140 activations taking place in New York City now through Nov. 23, these 12 events are can’t-miss moments.
MajorsNov 18, 2025
Lugano Diamonds Files for Bankruptcy, Looking for BuyerThe Chapter 11 filing follows the resignation of CEO Moti Ferder, who stepped down after an investigation into the company’s finances.
Events & AwardsNov 18, 2025
A Giant, Bejeweled Moldy Berry Is on Display in LAThe artwork is part of an exhibition featuring works by Kathleen Ryan, an artist known for her gemstone-studded rotting fruit sculptures.
SourcingNov 18, 2025
Another Diamond Company CEO Steps DownMark Wall, president and CEO of Canadian mining company Mountain Province Diamonds, will vacate his position next month.
CrimeNov 17, 2025
Police Searching for 2 Suspects in Murder of Father, Son Jewelers Faustino Alamo Dominguez and his son, 25-year-old Luis Angel Alamo, were gunned down following an armed robbery at their jewelry store.
