Research & News
Solid Carved Dark Gray Diamond Ring
Graphite needles create the dark gray color of a most unusual solid diamond ring carved from Canadian rough.
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.
Interesting Sapphires from Montana and Australia
Intriguing bicolor sapphires and spectacularly colored thin sapphire slabs are produced by mines in Rock Creek and Inverell, respectively.
Staurolite in Ruby
Conspicuous bright brownish red crystals in ruby matrix are the first recorded observations of staurolite in corundum.
Fluorescence Spectroscopy for Colored Pearl Treatment Screening
A nondestructive rapid screening technique uses fluorescence spectroscopy to identify treated colored pearls.
Bavenite in Quartz
Faceted quartz contains numerous unusual white radial inclusions identified as bavenite.