Copper-bearing gem tourmaline, known as Paraíba tourmaline after the location of its original discovery, is prized for its vivid blue to green color. This article explains GIA’s use of quantitative chemical analyses to distinguish samples from Brazil, Nigeria, and Mozambique.

An emerging corundum deposit in northeastern China is discussed.

At the GIA Carlsbad laboratory, the authors recently examined a cabochon of “bloodshot” iolite (containing red, eye-visible platelets of hematite) intergrown with a sunstone.

Each level of the vertical Hidden Gems exhibit offers a different theme at the San Diego Natural History Museum.

The Hong Kong laboratory recently examined a Burmese star ruby incorporating a significant amount of bismuth glass.

A cordierite with a color not seen in the GIA lab is examined in New York.

An overview of the Fall 2025 Gems & Gemology content.

A 37.41 ct natural rough diamond with distinct pink and colorless zones is examined at GIA’s Botswana laboratory.

Profiles the extraordinary life and work of Ben Kho, from a young entrepreneur in Cambodia to an award-winning gem cutter.

Grossular crystals cut along specific orientations reveal a distinct trapiche structure.

Describes the geology, mineralogy, and formation of granitic-composition pegmatites and provides a summary of their worldwide occurrences.

An overview of the Summer 2025 Gems & Gemology content.

Provides a comprehensive summary of the special optical effects in gemstones, including opalescence, chatoyancy, asterism, schiller, and iridescence, and investigates the submicron inclusions and nanotextures in each type of phenomenal stone.

GIA developed this guide so retailers can use fluorescence tests to help identify gems right in their own stores.