Article Search Results

Show Filters
Showing 31 results for "*"
Fancy Dark brown to Fancy black Marange diamonds
Black Diamonds from Marange (Zimbabwe): A Result of Natural Irradiation and Graphite Inclusions

Characterizes a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.

Read More

Recently discovered and legendary diamonds in the blue/gray/violet color range
Natural-Color Blue, Gray, and Violet Diamonds: Allure of the Deep

Summarizes data collected on more than 15,000 natural blue/gray/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this color range.

Read More

Grading the Hope Diamond

One of the most popular exhibits at the Smithsonian Institution, the stunning Fancy Dark grayish blue Hope diamond was formally graded by GIA’s gem laboratory.

Read More

Rough and faceted natural-color green diamonds.
Natural-Color Green Diamonds: A Beautiful Conundrum

Characterizes diamonds with exceptionally rare natural green color, based on GIA’s extensive database of samples.

Read More

Drilled natural pearls examined in this study.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemological and Radiocarbon Dating Study

Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.

Read More

The Wittelsbach Blue

This article describes what is known about the Wittelsbach Blue since it was first reported in 1666, and the gemological information released to date on this diamond.

Read More

Developments in Gemstone Analysis Techniques and Instrumentation During the 2000s

The first decade of the 2000s continued the trend of using more powerful analytical instruments to solve gem identification problems.

Read More

Hydrogen-rich Diamonds
Gray-To-Blue-To-Violet Hydrogen-Rich Diamonds from the Argyle Mine, Australia

The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds colored gray to blue to violet.

Read More

Nanocut Plasmaetched Diamonds
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.

Read More

A wide range of jewelry pieces with the round brilliant diamond cut
A Foundation for Grading the Overall Cut Quality of Round Brilliant Cut Diamonds

The GIA diamond cut grading system described here includes the components of brightness, fire, scintillation, polish, and symmetry, as well as weight and durability concerns, into a single overall grade for cut quality for standard round brilliants.

Read More