“Conch Shell” in Diamond
A transparent feather observed in a natural diamond resembles a conch shell.
Fireworks in Ruby
An unheated purplish red ruby cabochon displays a white double-star phenomenon.
Pyritic Inclusions in Oregon Sunstone
Examination of an Oregon sunstone sample reveals pyritic and copper inclusions.
Snowflakes in Opal
Laboratory Growth of Gem Materials and the Attempt to Replicate Nature
Provides an overview of processes for synthesizing gem materials and explains how unique growth conditions enable them to be separated from naturally formed gems.
Chrysoprase and Prase Opal from Haneti, Central Tanzania
Commercial quantities of gem-quality chrysoprase and green prase opal (nickel-bearing chalcedony and common opal, respectively) have been recovered from altered serpentinite deposits near Haneti, Tanzania.
Cutting Diffraction Gratings to Improve Dispersion (“Fire”) in Diamonds
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.
HPHT-Processed CVD Laboratory-Grown Diamonds with Low Color Grades
The Antwerp lab examines CVD laboratory-grown diamonds where HPHT processing resulted in relatively low color grades.
Imitation Rubellite Boulders
Specimens presented as rubellite tourmaline rough are found to be resin imitations with lead inserts.
Mixing of Natural Diamonds with HPHT Synthetic Melee
Screening reveals a surprise within a batch of synthetic diamond melee.
Winter 2011 G&G Lab Notes
This section, from the Winter 2011 issue of Gems & Gemology, is a compilation of interesting finds from GIA’s laboratories.
D-Color Natural IIa Diamond with Walstromite Inclusion
A diamond is proven to have a superdeep origin through an inclusion of CaSiO3-walstromite.
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.
Spring 2020 G&G Publication Information
This document provides the publication information for Gems & Gemology
Fall 2014 G&G Publication Info
This document provides the publication information for Gems & Gemology
From Single Source to Global Free Market: The Transformation of the Cultured Pearl Industry
Over the past 15 years a combination of market forces, environmental events, and scientific research has radically changed the cultured pearl industry.
“Soap Bubbles” in Yellow Sphene
A sample of yellow sphene displays a cloud of soap bubble–like inclusions with interference colors.
Trapiche Tourmaline from Zambia
Well-formed crystals of green tourmaline from northwestern Zambia show a growth pattern reminiscent of trapiche emerald/ruby when sliced perpendicular to the c-axis.
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