GIA Sees ‘Unusual’ Color Change in Sapphires During Stability Testing

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. 
 Related stories will be right here … 
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

The Latest

Myne London
CollectionsJul 12, 2024
Myne London to Support Malala Fund

The emerald supplier will donate a percentage of sales from its “Star Power” earrings to the nonprofit in support of girls’ education.

The Jewelry Symposium logo
Events & AwardsJul 12, 2024
The Jewelry Symposium Is Looking for Speakers

TJS is seeking jewelry manufacturing and technology experts to speak at its 2025 event.

Sculptural Freeform Earrings
CollectionsJul 12, 2024
Piece of the Week: Marrow Fine’s ‘Sculptural Freeform’ Earrings

The earrings were inspired by the landscape at Joshua Tree and Jean Arp’s abstract sculptures.

Untitled design.jpg
Brought to you by
The End of an Era? Lab-Grown Diamonds' Journey Towards Price Stability

As the demand for lab-grown diamond jewelry may still be increasing, the most notable change we are likely to see is price stabilization.

Madeline Fraser Gemist
EditorsJul 11, 2024
Q&A: Gemist CEO Madeline Fraser on Jewelry Visualization Technology

Fraser shares why she decided to shift from a direct-to-consumer retailer to a B2B technology company.

Weekly QuizJul 11, 2024
This Week’s Quiz
Test your jewelry news knowledge by answering these questions.
Take the Quiz
Jewelers of America learning workshop Providence logo
Events & AwardsJul 11, 2024
JA to Host Next Learning Workshop in Providence

The one-day workshop will be held July 17 at the Rhode Island School of Design.

Jewelers International Showcase Logo Statue
Events & AwardsJul 11, 2024
Registration Now Open for JIS Fall 2024

The jewelry trade show will take place in Miami Oct. 6-9.

1872 x 1052 Gemolite.jpg
Brought to you by
Meet Gemology’s Next Generation Microscope: GIA® Gemolite® NXT Professional Edition

GIA®’s most advanced microscope has new features to optimize greater precision and comfort.

Kyle Kuzma, D’Angelo Russell, Jalen Green, Jaime Jacquez Jr., Kevin Love, Josh Hart, and Seth Curry
MajorsJul 11, 2024
David Yurman Names 7 NBA Players as Brand Ambassadors

The partnership reinforces David Yurman’s position as a leader in men’s jewelry, said the company.

U.S. Customs and Boarder Protection Paperwork
CrimeJul 10, 2024
US Customs Seizes $10M in Counterfeit Jewelry

Officers intercepted three packages within 24 hours containing fake goods claiming to be from various luxury brands.

Matturi Fine Jewelry totem jewel
Events & AwardsJul 10, 2024
IAC’s Gold and Diamond Conference to Focus on ‘Expanding Horizons’

The 14th annual conference will host panels on cross-sector collaboration, industry sanctions, and more.

Immediate Connections
Events & AwardsJul 10, 2024
Women’s Art Center of the Hamptons to Host Jewelry Exhibition

“Immediate Connections” will be on view from July 18-21.

Navneet Gems salt & pepper sapphires
SourcingJul 10, 2024
Navneet Gems Launches Salt-and-Pepper Sapphires

Sourced from Tanzania, the stones feature a unique hematite inclusion.

Buccellati butterfly brooch
TrendsJul 10, 2024
Amanda’s Style File: Slither and Fly

Snakes, birds, and bugs are all the buzz this summer.

Peter Smith
ColumnistsJul 09, 2024
11 and ½ Thoughts on Leadership

From prioritizing “big rocks” to practicing transparency, Peter Smith explores what it takes to be an effective leader.

John Hardy bracelet and Wölffer Estate Summer in a Bottle rosé
CollectionsJul 09, 2024
John Hardy Toasts to Wölffer Estate With New Collection

The capsule collection is inspired by the Hamptons vineyard’s Summer in a Bottle rosé.

Fuli Gemstones peridot The Curious Gem
SourcingJul 09, 2024
The Curious Gem Now Carrying Fuli Peridot

The U.K.-based online supplier will offer calibrated stones under 1 carat.

Graff’s fancy yellow and white diamond necklace
CollectionsJul 09, 2024
See Graff’s New High Jewelry Creations

The jewels are inspired by modern architecture with a focus on the play of light and movement.

Ravi Bhansali and Isidore Mörsel
SourcingJul 08, 2024
AWDC Re-Elects Isidore Mörsel as Board President

Ravi Bhansali has been elected vice president.

Michael Richards and Clayton Bromberg of Underwood’s
IndependentsJul 08, 2024
Underwood’s Appoints Michael Richards as President

Clayton Bromberg will remain as chairman of the Florida jeweler.

Yale Peabody Museum quartz sandstone concretion
SourcingJul 08, 2024
Yale Peabody Museum to Reopen Hall of Minerals

The Connecticut museum will unveil the newly renovated galleries on July 9.

Neiman Marcus Fort Worth Texas
MajorsJul 05, 2024
Saks Fifth Avenue Owner to Acquire Neiman Marcus

The deal is valued at $2.65 billion.

Cece Jewellery Insignia Medallion
CollectionsJul 05, 2024
Piece of the Week: Cece Jewellery’s ‘Insignia’ Medallion

Spin the medallion’s diamond arrow to find out your fate.

SourcingJul 05, 2024
Lucara Names New VP of Mineral Resources

Lauren Freeman, a Ph.D. with more than 25 years of experience in mining, has joined the company.

2004 case.png
Supplier BulletinJul 03, 2024
CASE Awards: Celebrating Creativity & Craftsmanship for 30 Years

Sponsored by Jewelers of America

Sissy’s Log Cabin William Jones IV
IndependentsJul 03, 2024
William Jones IV Promoted to President of Sissy’s Log Cabin

The third-generation leader succeeds Lamar McCubbin, who resigned last month after 11 years in the role.

John Youkilis and Craig MacBean
MajorsJul 03, 2024
Ostbye & Anderson Acquires Fellow Midwest Manufacturer

The Minneapolis-based company bought Victor Corporation, which has been making jewelry in Cincinnati since 1946.


This site uses cookies to give you the best online experience. By continuing to use & browse this site, we assume you agree to our Privacy Policy