Research & News
New Emerald Locality in Southern California
An emerald containing an unusual citrine inclusion heralds a new pegmatitic deposit in the Julian Mining District in San Diego County.
GIA Knowledge Sessions
Engage in webinars on the most diverse and pressing issues in gemology today, including gemstone origin, laboratory-grown stones and new discoveries in field gemology.
Blue “Graining” in Green-Yellow Diamond
Unusual color zoning likely indicates multiple treatments of a Fancy Intense green-yellow diamond.
Inclusions in Kenyan Rubies from the John Saul Mine
Very similar inclusion scenes featuring needles and thin films make rubies from Kenya hard to distinguish from Mogok rubies.
Study of Rare Diamonds Unlocks More of Earth's Secrets
Scientists at GIA continue to delve deep into earth's geologic history, using diamonds' distinctive characteristics to go – virtually – where no scientist has ever gone.
Large Type IIa Diamond from Arkansas, USA
A surprising find from Crater of Diamonds State Park reveals a natural diamond remarkable in both size and clarity for its U.S. origin.