Origins of Color in Brown Mammoth Ivory
Investigates the mineral and chemical compositions and surface morphology characteristics of brown mammoth ivory to identify the origins of its brown color.
Spring 2023 Auction Highlights
After a slow start, the spring 2023 auction season ends with multiple broken records.
An Iridescent “Insect Wing” in Diamond
A feather inclusion with iridescence caused by thin-film interference in diamond resembles an insect wing.
Rainbow Mountain in Natural Diamond
An iridescent feather inclusion in natural diamond bears resemblance to Rainbow Mountain in Peru.
A New Treatment: Creating Phantom Structure in Opal
A newly developed treatment creates a phantom structure in opal visually similar to natural phantom opal.
Patchy Yellow Trigon
Isolated nitrogen confined to the outer surface of a 0.98 ct diamond causes “yellow skin.”
Triplite Inclusions in Quartz from Yaogangxian, China
Pinkish orange crystal inclusions in a faceted quartz are identified as the rare phosphate mineral triplite.
A Fascinating Large South Sea Bead Cultured Pearl
An exceptionally large South Sea bead cultured pearl is examined at GIA’s Mumbai laboratory.
Yellow Zoning in Pink Diamonds
Unusual natural pink diamonds displaying faint yellow color zoning and strong yellow fluorescence are studied in the Carlsbad laboratory.
Night Sky in Yellow Sapphire
Fiber-optic light creates a night sky scene in a yellow sapphire from Madagascar.
Interesting Metallic Platelets in a Brazilian Paraíba Tourmaline
Microscopic observation unveils the first known instance of skeletal metallic inclusions in Brazilian Paraíba tourmaline.
Susan Jacques Receives Robert M. Shipley Award
GIA president and CEO Susan Jacques receives the American Gem Society’s highest honor.
2023 Sinkankas Symposium
The Nineteenth Annual Sinkankas symposium, held at GIA’s Carlsbad, California campus, focused on gems and minerals of San Diego County.
Guest in Garnet: Metal Sulfide?
An intriguing metallic inclusion is observed in a faceted garnet.
Solid Laboratory-Grown Single-Crystal Diamond Ring
The quality and size of this 4.04 ct CVD-grown diamond ring demonstrate the advancing technology in laboratory-grown diamonds.
Ethical Supply Chain Practices in Africa with Virtu Gem
A look at Virtu Gem, a company dedicated to improving artisanal mining practices in Africa.
Quarterly Crystal: Columbite(?) in Beryl
Examination of a gem-quality aquamarine crystal reveals an inclusion cluster presumed to be columbite.
A “Flying Insect” in Diamond
A partially exposed orange garnet inclusion with surrounding fractures resembles a flying insect in a brownish yellow diamond.
Gemological Characterization of Montana Sapphire from the Secondary Deposits at Rock Creek, Missouri River, and Dry Cottonwood Creek
Examines the mining history and geological characteristics of the three secondary sapphire deposits in the state of Montana, as well as the properties of these sapphires (unheated and heat-treated).
Pinctada radiata Atypical Bead Cultured Pearls from the UAE
GIA’s Mumbai laboratory reports on pearl samples from a culturing experiment by the Suwaidi Pearl Farm in the UAE.
.jpg "YMAL GIA Ed")
