Identification of “Pistachio” Coloured Pearls Treated by Ballerina Pearl Co.
A report on the colour treatment process for these intensely greenish yellow to yellowish-green cultured pearls and the techniques for identifying them.
Variscite from Central Tajikistan: Preliminary Results
A look at the gemmological properties and chemical composition of this light blue to light green to green gem material, which is suitable for cabochon cutting.
Observations on CVD-Grown Synthetic Diamonds: A Review
Explores statistical data and defining characteristics of gem-quality CVD synthetic diamonds examined by GIA since 2003.
An Introduction to Photoluminescence Spectroscopy for Diamond and Its Applications in Gemmology
Presents the underlying physics and methodology of this analytical technique, which has become an essential tool in identifying treated and synthetic diamonds.
An Early Byzantine Engraved Almandine from the Garibpet Deposit, Telangana State, India: Evidence for Garnet Trade Along the Ancient Maritime Silk Road
Analyses the chemical composition and inclusion characteristics of this ancient artefact.
Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions
Characterises a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.
Natural-Colour Blue, Grey and Violet Diamonds: Allure of the Deep
Summarises data collected on more than 15,000 natural blue/grey/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this colour range.
Inclusions in Natural, Synthetic and Treated Ruby
Provides a visual guide to the internal features of natural, synthetic and treated rubies.
Real-Time Microradiography of Pearls: A Comparison Between Detectors
Compares the image quality provided by real-time microradiographic imaging (RTX) units fitted with two different detectors: an image intensifier (II) and a flat panel detector (FPD).
Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards
Presents a group of corundum standards developed by GIA to improve the accuracy and efficiency of its laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) instruments.