Is There a Difference Between Natural and Laboratory-Grown Diamonds?
Learn about the differences – and similarities – between natural and laboratory-grown diamonds, and how GIA’s researchers and grading laboratories can tell the difference
A Repaired Diamond
A marquise-cut diamond is found to have been broken and reassembled with an unknown adhesive.
Large Faceted Afghanite
A report on the largest facet-grade afghanite seen in the GIA gem identification department.
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.
Dyed Quartzite Imitation of Ruby-in-Zoisite
Beads appearing to be ruby-in-zoisite are revealed to be dyed quartzite.
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.