Research & News
The Largest Diamond Discovered in North America
GIA examines a 552.7 ct diamond from the Diavik mine in Canada.
Zircon Cluster in Ethiopian Sapphire
The presence of these zircon clusters might help separate Ethiopian sapphire from other basalt-related sources.
A Rare Ruby from Montana
An exceptional ruby specimen is identified with a Montana of origin in the Carlsbad lab.
How Do Diamonds Form in the Deep Earth?
G&G’s newest section explores how diamonds form in the deep earth.
Season’s Sales: US Up 4% to 5%, But China Continues to Lag
The U.S. holiday season saw strong sales, but China continues to struggle. Plus: diamond market report and lab-grown diamond sales.
Coated Pink Synthetic Moissanite
A pink synthetic moissanite is coated with a thin colored film, raising questions about the natural origin of its color.