Article Search Results

Three pieces of labradorite with yellow, blue and green flashes of color.

Article

Optical Effects of Phenomenal Cabochons

Sharon Bohannon, November 11, 2016

Learn how the structure, inclusions and properties of some gemstones interact with light to create unusual visual effects.

Article

GIA Researchers Evaluate ‘Light Performance’ and Diamond Cut

Ilene Reinitz, Al Gilbertson and Ronnie Guerts, March 12, 2020

The phrase “light performance” gets a lot of loose use in the diamond trade, but what does it mean when someone is actually looking at a diamond?

A face-up view of a cushion cut diamond with blue color.

Article

Gems & Gemology’s 7 Most Unusual Encounters from 2019

Stuart Overlin, Brooke Goedert and Kellie Giordano, December 13, 2019

Check out some of the most interesting and unusual diamonds and coloured stones submitted to GIA’s laboratories in 2019.

The round brilliant is the most popular diamond cut. Because of its popularity, assessment of this cut has been the subject of considerable research. Courtesy of Harold & Erica Van Pelt.

Article

Diamond Cut: The Wow Factor

Amanda J. Luke, January 14, 2016

Learn the basics of the GIA Cut Grading System for round brilliant cut diamonds to help pick out your perfect diamond.

Article

Pyrope Garnet and Montana Sapphires Highlight Winter 2015 G&G

Russell Shor, February 1, 2016

G&G Brief presents an overview of the content of the Winter 2015 issue of Gems & Gemology.

Cutting Diffraction Gratings to Improve Dispersion (“Fire”) in Diamonds

Al Gilbertson, Benjamin Gudlewski, Mary Johnson, George Maltezos, Axel Scherer, and James Shigley

A new microlithography process developed to create high-resolution diffraction grating patterns on portions of certain facets can improve the dispersion of light and thus the amount of “fire” in a diamond.

Article

Summer 2015 G&G: Dual-Stars, Photomicrography Guide, Rubies from Tajikistan, New Micro-World Section

Russell Shor, August 14, 2015

G&G Brief presents an overview of the content of the Summer 2015 issue of Gems & Gemology.

Abstract Header from the 2009 issue of Gems & Gemology

Abstracts; Summer 2009

Brendan M. Laurs, Thomas W. Overton

This article, from the Summer 2009 issue of Gems & Gemmology, is a compilation of abstracts of important gemmology-related articles published outside of Gems & Gemmology.

A History of Diamond Treatments

Thomas W. Overton and James E. Shigley, March 1, 2008

Modern gemmologists and diamantaires are faced with a broad spectrum of colour and clarity treatments ranging from the simple to the highly sophisticated.

Diamonds in Their Initial States, After UV Exposure and After Heating

Colour Alterations in CVD Synthetic Diamond with Heat and UV Exposure: Implications for Colour Grading and Identification

Rizwan U. A. Khan, Philip M. Martineau, Bradley L. Cann, Mark E. Newton, Harpreet K. Dhillon, and Daniel J. Twitchen

In response to heat and UV exposure, some synthetic diamond gemstones grown by chemical vapor deposition exhibit large, reversible changes in colour.

Article Search Results

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Gemstones

Article Search Results

Types

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Gemstones

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