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.
Combination of Phenomena in Star and Cat’s-Eye Color-Change Sapphire
Both asterism and chatoyancy are observed in a color-change sapphire.
Spring 2022 Auction Highlights
Large near colorless, blue, and yellow diamonds broke auction records at Christie’s and Sotheby’s in the first half of 2022.
The Type IIb De Beers Cullinan Blue Diamond
GIA’s New York laboratory reports on a 15.10 ct Fancy Vivid blue cut-cornered rectangular step cut named the De Beers Cullinan Blue diamond.
Night Sky in Yellow Sapphire
Fiber-optic light creates a night sky scene in a yellow sapphire from Madagascar.
Spring 2023 Auction Highlights
After a slow start, the spring 2023 auction season ends with multiple broken records.
Gems Formed in Metamorphic Rocks
Gemstones formed in metamorphic environments offer insights into the earth’s history and the evolution of tectonic activity that led to their formation.
A Fascinating Large South Sea Bead Cultured Pearl
An exceptionally large South Sea bead cultured pearl is examined at GIA’s Mumbai laboratory.
Patchy Yellow Trigon
Isolated nitrogen confined to the outer surface of a 0.98 ct diamond causes “yellow skin.”
Interesting Metallic Platelets in a Brazilian Paraíba Tourmaline
Microscopic observation unveils the first known instance of skeletal metallic inclusions in Brazilian Paraíba tourmaline.
Rainbow Mountain in Natural Diamond
An iridescent feather inclusion in natural diamond bears resemblance to Rainbow Mountain in Peru.
Triplite Inclusions in Quartz from Yaogangxian, China
Pinkish orange crystal inclusions in a faceted quartz are identified as the rare phosphate mineral triplite.
