Winter 2025 G&G Available Now

Erica Zaidman

February 2, 2026

The Winter issue of Gems & Gemology has much in store for readers in our feature articles—from Montana sapphire and Arkansas turquoise in the United States to emerald from central China. Our regular sections are packed with exciting content as well, including highlights from the Converge 2025 conference and a tour of the GIA Museum’s latest exhibit.

The Primary Sapphire Occurrence at French Bar Sill Along the Missouri River, Near Helena, Montana

A team of gemologists led by independent researcher Robert Kane investigates the primary sapphire deposit found at the French Bar sill along Montana’s Missouri River. Studying sapphires in their natural rock matrix, as well as in rough, semi-polished, and fully faceted forms, their findings reveal that the inclusions and trace element chemistry of these sapphires closely mirror those of stones recovered from secondary sources in Montana.

Characterization of Emeralds from Zhen’an County in Shaanxi, China

Yi Guo and fellow researchers present a detailed study of a recently discovered emerald source in Zhen’an County in Shaanxi Province, China. They examine the gemological properties, spectroscopic features, and trace-element composition of the emeralds using both standard and advanced testing methods.

Arkansas Turquoise: Evaluating the Mona Lisa Mine, Polk County

GIA’s Alexander Goodsuhm provides a turquoise study from the reopened Mona Lisa mine in Arkansas. Combining on-site fieldwork with gemological testing and advanced analytical techniques, the author confirms that the material from the mine is indeed true turquoise.

Lab Notes

GIA’s global laboratory staff present their latest findings in the Lab Notes section, including reports on filled natural hollow heart-shaped pearls, an extraordinary cat’s-eye boulder opal, and a rare faceted armenite.

Micro-World

The Micro-World section continues to showcase fascinating gemstone inclusions, with a striking metal sulfide crystal in spinel, flame patterns resembling fireworks on a conch pearl, vivid blue lazurite inclusions in scapolite, and more.

Colored Stones Unearthed

Colored Stones Unearthed returns to cover the remarkable variety of gemstone deposits, exploring how different gem minerals occur together and the geological conditions that create each unique environment.

Gem News International

Gem News International begins with extensive coverage of the recent Converge 2025 conference, providing summaries of the presentations, posters, and hands-on sessions held during the four-day event. The section continues with various reports from contributors worldwide, such as new red garnet production from northern Vietnam and the increase in deceptive gem specimens being sold in Pakistan.

In the Spotlight

Lastly, we highlight the GIA Museum’s current Temples and Treasures of Southeast Asia exhibit, which features the extraordinary crystals and gems central to the cultures of the area.