Ginger Garnet, “Fancy” Tanzanite
Garnets and a wide variety of tanzanite at the Tucson gem shows.
High-End Colored Gems
A unique assortment of colored gemstones as seen at the GJX show in Tucson.
Tsavorite Garnet and Mahenge Red Spinel
A discussion of the current demand for tsavorite and spinel in today’s market.
Analysis of Melee Diamonds Using FTIR Spectroscopy
Artificially Irradiated Color-Change Diamonds
Examination of two chameleon diamonds reveals color enhancement through artificial irradiation.
Conservation Concerns over Use of Tridacna Shell in Imitation Pearls
The New York lab investigates the use of the shells of Tridacna species as imitation pearls.
Diamond in Diamond
A Fancy black round brilliant diamond has an inclusion that is revealed to be a natural diamond crystal.
HPHT Synthetic Diamond Melee in High-Quality Jewelry Piece (英語)
The New York lab discovers a synthetic melee diamond in a pendant, underscoring the importance of testing for undisclosed synthetics.
Large HPHT-Grown Synthetic Diamonds Examined in GIA’s Hong Kong Laboratory (英語)
Examination of the largest HPHT synthetic diamonds GIA has examined so far demonstrated significant progress in this growth technology.
Large Natural Quahog Pearl
A purple non-nacreous specimen is revealed to be a natural northern quahog pearl.
Pink and Reddish Purple Cobaltocalcite
GIA's Bangkok lab investigates the coloration and gemological properties of this striking mineral specimen.
Books: Van Cleef & Arpels: Treasures and Legends
CVD Synthetic Diamond with Unstable Color Centers
