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Ruby

Ruby is the most valuable variety of the corundum mineral species, which also includes sapphire.

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Fine Mogok Ruby

This fine 2.58-ct. ruby is from Myanmar’s classic Mogok deposit.

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Extraordinary

Ruby’s extraordinary red color is caused by traces of chromium.

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Mixed Cut

Like many fine rubies, this example is fashioned as a mixed cut.

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Calcite Matrix

These exceptional ruby crystals on calcite are from Mogok, Myanmar.

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Origin In Marble

The snow white calcite matrix hints at the ruby crystal’s origin in marble.

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Ruby Crystal

The characteristic form of this ruby crystal allows it to be recognized.

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Tools

Research

Gem corundum colored by a single chromophore
A Quantitative Description of the Causes of Color in Corundum

Presents a quantitative means of determining the causes of color in a gem material, using corundum’s six major chromophores as an illustration.

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Two blue sapphires side-by-side
Article
G&G Announces Most Valuable Article Awards

G&G announces the winners of the Dr. Edward J. Gübelin Most Valuable Article Awards for 2019.

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Man stands in front of an audience giving a lecture – projection screen with image to his right.
Article
Not All That Glitters is Gold — Sometimes it is Mozambican Rubies

Learn about Mozambican rubies, including their mining history, characteristics and market demand.

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A large group of people in a hallway.
Article
Coronavirus May Cut Chinese Demand, Diamond Companies See Better Times

The economic impact of the coronavirus in mainland China and Hong Kong. Plus, an update on the diamond market and gold jewelry.

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Sapphire crystal from Kataragama, Sri Lanka
Geology of Corundum and Emerald Gem Deposits

Over the last two decades, knowledge of the formation of gem deposits has improved significantly. This article reviews the state of our knowledge of the geology and genesis of gem corundum and emerald deposits.

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Field gemologists sort through gem gravel in Myanmar
Field Gemology: Building a Research Collection and Understanding the Development of Gem Deposits

With more than 90 field expeditions on six continents since 2008, GIA has accumulated over 22,000 colored stone reference samples. This extensive collection of colored stones with known origins supports GIA’s research on geographic origin determination.

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Confocal Raman spectroscopy
A Review of Analytical Methods Used in Geographic Origin Determination of Gemstones

Geographic origin determination relies on a combination of gemological observations and advanced analytical tools. This contribution reviews the analytical methods commonly used to establish origin.

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Ruby and diamond earrings from Mong Hsu
Geographic Origin Determination of Ruby

The world ruby market has undergone dramatic change in recent years, especially with the development of ruby mining in Mozambique. This contribution outlines GIA’s methods and criteria for establishing the geographic origin of ruby.

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Gemstone classics from sources old and new
The Geographic Origin Dilemma

An overview of the geographic origin complexities facing the gem and jewelry industry today.

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Two people walk past a Kay Jewelers storefront.
Article
Jewelry Sales Show Modest Rise; Higher End Soars

U.S. holiday jewelry sales increased slightly from 2018. Online buying surged, while foot traffic in retail stores slowed.

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