Grading

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.

20221214_GIA-sapphires.jpg
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 GIA.edu.

The Latest

Anglo American’s Quellaveco copper mine in Peru
SourcingSep 09, 2025
Anglo American to Merge With Canadian Copper Miner

Anglo plans to merge with Teck Resources Ltd. to form Anglo Teck. The deal changes nothing about its plans to offload De Beers.

The Mellon Blue diamond
AuctionsSep 09, 2025
‘The Mellon Blue’ to Return to Auction, This Time at Christie’s

The 9.51-carat fancy vivid blue diamond, which set two world auction records at Sotheby’s in 2014, is estimated to fetch up to $30 million.

Dianne Batista Phillips Auctions
AuctionsSep 09, 2025
Phillips Names Dianne Batista Head of Jewels, New York

The industry veteran joins the auction house as it looks to solidify its footprint in the jewelry market.

reDollar-fine-jewelry-department.jpg
Brought to you by
reDollar.com Is Rolling Out the Next Level Jewelry, Diamond & Watch Consignment Program

With their unmatched services and low fees, reDollar.com is challenging some big names in the online consignment world.

Anastacia Lauren, Elle Jerge, Logan Nye
MajorsSep 09, 2025
MJSA Education Foundation Announces 2025 Scholarship Winners

The nonprofit awarded four students pursuing a professional career in jewelry making and design with $2,250 each.

Weekly QuizSep 04, 2025
This Week’s Quiz
Test your jewelry news knowledge by answering these questions.
Take the Quiz
Korman jewelry store Austin
IndependentsSep 08, 2025
Take a Look Inside the New Korman Store in Austin

The Texas-based jeweler has also undergone a brand refresh, debuting a new website and logo.

Logos for Manufacturing Jewelers & Suppliers of America and Jewelers of America
MajorsSep 08, 2025
MJSA Is Officially Now Under JA’s Umbrella

The two organizations have finalized and signed the affiliation agreement announced in May.

japac-btyb.png
Brought to you by
Rallying Call for the Jewelry Industry on Tariffs and Other Key Issues

Jewelers of America is leading the charge to protect the industry amidst rising economic threats.

Sothebys JAR and Suzanne Belperron jewels
AuctionsSep 08, 2025
Sotheby’s To Auction ‘Exceptional’ Collection of JAR, Suzanne Belperron Jewels

The single-owner sale will headline Sotheby's inaugural jewelry auction at the Breuer building, its new global headquarters, this December.

A street in Carlsbad California
Events & AwardsSep 08, 2025
27 Can’t-Miss Converge Sessions, Events

From sunrise yoga to tariffs talks, these are some events to check out at the upcoming inaugural event.

National Jeweler columnist Peter Smith
ColumnistsSep 05, 2025
Peter Smith: A Lasting Lesson From Maurice Tempelsman

Smith recalls a bit of wisdom the industry leader, who died last week, shared at a diamond conference years ago.

Jamie Turner Victoria Labradorite Necklace
CollectionsSep 05, 2025
Piece of the Week: Jamie Turner’s ‘Victoria’ Necklace

The “Victoria” necklace features a labradorite hugged by diamond accents in 18-karat yellow gold.

Stock image of the U.S. Supreme Court
Policies & IssuesSep 05, 2025
Trump Takes Tariffs Case to the Supreme Court

Two lower courts have moved to block the import taxes, which will remain in place as the legal battle continues.

Patrick Mahomes Hublot campaign
WatchesSep 05, 2025
Patrick Mahomes Is the New Hublot Brand Ambassador

The Kansas City Chiefs quarterback shares Hublot’s dedication to pursuing greatness, the Swiss watchmaker said.

gia-edu main image.png
Supplier BulletinSep 04, 2025
A Brilliant Future Is Here

Sponsored by GIA

Lucara pink diamond
SourcingSep 04, 2025
Lucara Unveils Unusual 37-Carat Pink Diamond

The Type IIa stone, recovered from Botswana’s Karowe diamond mine last month, features unique coloration.

Shot from Breitling new NFL campaign
WatchesSep 04, 2025
Breitling Takes Its NFL Game to the Next Level

Breitling is now the NFL’s official timepiece partner, a move that puts the brand in front of the millions of Americans who watch football.

NYC Jewelry, Antique, & Object Show Autumn 2025
Events & AwardsSep 04, 2025
The NYC Jewelry, Antique, & Object Show Returns in November

NYCJAOS is set for Nov. 21-23 in New York City’s Chelsea neighborhood.

Fabergé x Gemfields Malaika Egg
SourcingSep 03, 2025
Gemfields Confirms Completion of Fabergé Sale

U.S.-based investment company SMG Capital LLC is the new owner of the luxury brand.

Claire’s storefront
MajorsSep 03, 2025
These Are the Nearly 300 Claire’s Stores Set to Close

A new court filing details the locations of the stores that will close, as well as the 830 that will remain open.

Stuller’s Tools, Equipment, & Metals and Findings & Metals Catalogs
MajorsSep 03, 2025
Stuller Releases 2 New Catalogs

The new catalogs are “Tools, Equipment, & Metals” and “Findings & Metals.”

Effy Jewelry Multicolor Sapphire Bangle
TrendsSep 03, 2025
Amanda’s Style File: A Perfect Birthstone

Sapphire’s variety of colors make it the perfect birthstone for September.

Woman with hands crossed wearing jewelry
FinancialsSep 02, 2025
Lab-Grown Diamonds, Lower-Priced Fashion Jewelry Drive Signet Jewelers’ Q2 Sales

The retailer has raised its guidance after seeing total sales increase 3 percent in the second quarter, beating expectations.

Jean-Christophe Bédos Birks
MajorsSep 02, 2025
Birks CEO Jean-Christophe Bédos Steps Down

Niccolò Rossi di Montelera, executive chairman of the board, was appointed as interim CEO.

Harry Winston Ginza Flagship Exterior, Interior
MajorsSep 02, 2025
Harry Winston Opens Its Largest Flagship in Japan

The three-floor space also features the jeweler’s largest VIP salon in Japan and offers an exclusive diamond pendant.

All Hours: Stephanie Gottlieb Fine Jewelry x Oak and Luna Campaign Imagery
CollectionsSep 02, 2025
Stephanie Gottlieb Debuts Silver Designs in ‘All Hours’ Collab

The collection is a collaboration between Stephanie Gottlieb Fine Jewelry and Oak and Luna, focusing on understated essentials.

Sothebys The Desert Rose orangy pink diamond collectors week
AuctionsAug 29, 2025
Sotheby’s UAE Sale to Feature 32-Carat Fancy Vivid Orangy Pink Diamond

The highlight of a single-owner jewelry and watch collection, it’s estimated to fetch up to $7 million at auction this December.

×

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