Summer 2021 G&G Available Now

Gems & Gemology Summer 2021 In Brief

The Summer issue bursts with exciting topics. We open with an important question in the diamond industry—how fluorescence intensity impacts diamond appearance and how to quantify those effects scientifically. Pearls are the focus of the next two articles, which identify the color origin of Chinese “Edison” freshwater pearls and present a classification system based on size, shape, color, luster, surface, matching, and nacre quality, respectively. Lastly, a field report highlights the bustling gemstone trading hub in Peshwar, Pakistan, known as the “intersection of anxiety.”

Measurement and Characterization of the Effects of Blue Fluorescence on Diamond Appearance

The lead article by Yun Luo and co-authors studies the effects of blue fluorescence on diamond appearance, particularly when it comes to perceived transparency and color. Results show that fluorescence intensity only occasionally impacts visible color and does not cause haziness by itself. The authors present methods to quantify these effects instrumentally.

Detection of Color Treatment and Optical Brightening in Chinese Freshwater “Edison” Pearls

A research team led by Chunhui Zhou provides an in-depth study on a group of 23 freshwater “Edison” pearls to distinguish their color origin. Various gemological and advanced instrumental techniques identified the use of color treatment and optical brightening agents in these popular cultured pearls.

Pearl Classification: The GIA 7 Pearl Value Factors

Affectionately known as “The Queen of Gems,” pearls have been cherished throughout history, and their popularity continues to grow in the market. Joyce Wing Yan Ho and Sally Chan Shih discuss the GIA 7 Pearl Value Factors for classifying various appearances and qualities. A beautiful wall chart accompanies this article.

Namak Mandi: A Pioneering Gemstone Market in Pakistan

This field report by Habib Ur Rehman and co-authors describes Namak Mandi’s transformation a salt market in Peshawar to Pakistan’s largest rough gemstone trading hub. The authors highlight pricing and trading techniques, the local gemstone supply chain, and traditional cutting practices to save weight.

Lab Notes

GIA laboratory staff members present their latest findings in the Lab Notes section, including a social media–worthy Melo pearl with an intense natural color, a beaded opal strand displaying striking play-of-color, and a flux-grown ruby containing chrysoberyl inclusions.


The Micro-World section, dedicated to the inner world of gemstones, features an iridescent abalone shell reminiscent of a topographic map, a polished quartz crystal displaying unusual bent rutile needles, and blue beryl crystals with heavily etched surfaces that are reportedly from Khyber Pakhtunkhwa in Pakistan.

Gem News International

Finally, GNI correspondents from around the world report on natural freshwater pearls from three European countries, mobile inclusions in quartz, multi-color Kenyan sapphires, and the reopening of the Mignone Halls of Gems and Minerals at the American Museum of Natural History in New York.

Brooke Goedert is associate editor of Gems & Gemology at GIA in Carlsbad, California.