Article Search Results

Show Filters
Showing 37 results for "*"
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

Brazilian Diamonds: A Historical and Recent Perspective

Recounts the history, geology, and notable localities of diamond mining in Brazil, and outlines plans for future diamond production.

Read More

The 135.74 ct Grand Sapphire
The Grand Sapphire of Louis XIV and The Ruspoli Sapphire: Historical and Gemological Discoveries

Archival research and gemological characterization reveal the true story of this 135.74 ct blue sapphire from the French crown jewels.

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

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

Color bars on top and sides of 3,019 ct rough opal
The Challenges of Cutting a Large Gem Opal Rough

A first-person account of cutting a 3,019 ct piece of white opal to create a 1,040 ct gem with play-of-color across the surface.

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

Ruby and Sapphire Production and Distribution: A Quarter Century of Change
Ruby and Sapphire Production and Distribution: A Quarter Century of Change

During the past 25 years, the corundum market has been transformed from one of medium to high-priced gems to one that encompasses nearly all price ranges.

Read More

Characterizing Natural-Color Type IIB Blue Diamonds

More than 400 blue diamonds were studied at the GIA Gem Trade Laboratory over several years to reveal additional information about the relationships between their color, clarity, and other gemological properties.

Read More

Color Grading “D-to-Z” Diamonds at the GIA Laboratory

This article discusses the history and ongoing development of GIA's color grading system, and explains how its laboratory applies it.

Read More