Large HPHT-Treated Blue Type IIb Diamond
Properties of, and theories on color zoning exhibited by, the largest HPHT-treated blue diamond graded by GIA.
Separating Glass-Filled Rubies Using the DiamondView
The DiamondView instrument is able to identify glass as the filler in a pair of heart-shaped rubies.
Nephrite Bracelet with Filled Cavity
A jade bracelet contains unusual fillers, used to create a smooth surface.
Strong Fluorescence in B-Jade Impregnated with Wax
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.
Colombian Emerald Industry: The New Generation
Luis Gabriel Angarita and Edwin Molina share their experiences and perspective on the Colombian emerald industry.
Turquoise from Western Arkansas
A report on turquoise from the only known U.S. deposit outside of the Southwest.
Irradiated and Annealed Blue Type Ia Diamond
Examination shows that a diamond was subjected to a multi-step process in order to introduce a blue color.
Fancy Deep Brown-Orange CVD Synthetic Diamond
A CVD-grown diamond shows an unexpected treatment-caused color.
Fracture-Filled Diamond with "Rainbow" Flash Effect
The material used to fill a large fracture in a diamond yields an unexpected iridescence under two different illuminations.
Unheated and Unusual Colors
Margit Thorndal of Madagascar Imports offers her perspective on the colored stone market.