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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.

A row of various shaped cut and polished pink diamonds.

Article

Why are Pink Diamonds Pink? GIA Researchers Dive Deep into their Crystal Structure

Russell Shor, October 18, 2019

GIA researchers analysed more than 90,000 natural pink diamonds to better understand how these rare and beautiful diamonds formed and got their colour.

Two white jade bracelets with dark color patches.

Nephrite Bracelet with Filled Cavity

Jianjun Li, Guihua Li, and Haixia Chen, August 9, 2018

A jade bracelet contains unusual fillers, used to create a smooth surface.

The wax-impregnated bangle (left) showed bluish fluorescence under long-wave UV.

Strong Fluorescence in B-Jade Impregnated with Wax

Larry Tai-An Lai, August 9, 2018

A bangle is an example of the misconception that B jade is only impregnated by resin, when in fact wax-impregnated jadeite is also considered B-jade.

These rubies were determined to be glass filled, partly due to the use of the DiamondView.

Separating Glass-Filled Rubies Using the DiamondView

Larry Tai-An Lai, August 9, 2018

The DiamondView instrument is able to identify glass as the filler in a pair of heart-shaped rubies.

HPHT-treated blue diamond (left) with ragged-looking graphitization around an inclusion (center) and high-order interference colors with crossed-polarizing filters (right).

Large HPHT-Treated Blue Type IIb Diamond

Evan M. Smith, Paul Johnson, and Kyaw Soe Moe, August 9, 2018

Properties of, and theories on colour zoning exhibited by, the largest HPHT-treated blue diamond graded by GIA.

These two opals were represented as natural-color blue and pink opal from Mexico.

Update on Dyed Hydrophane Opal

Edward Boehm and Nathan Renfro, January 26, 2018

Opal purportedly from a new deposit is found to be dyed.

This 20.60 ct specimen was purchased by the client as a “natural white pearl.”

Filled Pearl with Surface Features

Larry Tai-An Lai, January 26, 2018

A pearl, thought to be natural, is revealed to be a bead-cultured specimen with a pre-drilled nucleus.

Top: The drilled green briolettes. Bottom: Fluid inclusions, crystals, and two-phase inclusions.

Coated Beryl Imitating Emerald

Larry Tai-An Lai, January 26, 2018

Coating on a beryl demonstrates the importance of thorough examination of jewellery and gem materials.

Inclusions in Natural, Synthetic and Treated Ruby

Nathan D. Renfro, John I. Koivula, Jonathan Muyal, Shane F. McClure, Kevin Schumacher, and James E. Shigley, January 26, 2018

Provides a visual guide to the internal features of natural, synthetic and treated rubies.

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