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Sapphire
The name “sapphire” can also apply to any corundum that’s not ruby red, another corundum variety.
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Sapphires from the Andranondambo Region, Madagascar
Since 1993, large amounts of gem-quality sapphires from the Andranondambo region of southern Madagascar have entered the international gem market.
The Yogo Sapphire Deposit
Yogo Gulch, discovered more than 100 years ago, is one of four major sapphire-producing areas in Montana, United States.
Ruby and Sapphire from the Southern Ural Mountains, Russia
Primary occurrences of ruby, pink sapphire, sapphires of other colors, and spinel have been found in marbles in the Ural Mountains.
Heat Treating the Sapphires of Rock Creek, Montana
Renewed interest in large-scale commercial mining of Montana sapphires motivated a detailed study of the heat treatment of sapphire from the Rock Creek deposit.
Update on Diffusion-Treated Corundum: Red and Other Colors
Blue diffusion-treated sapphires have become a subject of considerable controversy since their introduction in significant quantities a few years ago.
Status of Ruby and Sapphire Mining in the Mogok Stone Tract
Burma, now named Myanmar, has for centuries been considered the world's preeminent source of fine rubies.
The Identification of Blue Diffusion-Treated Sapphires
Blue diffusion-treated sapphires are becoming more prevalent than ever before.
Carbon Dioxide Fluid Inclusions as Proof of Natural-Colored Corundum
An important clue in identifying natural-colored corundum is the presence of carbon dioxide fluid inclusions.
The Chanthaburi-Trat Gem Field, Thailand
Thailand has become the world's major source of gem ruby.
Sri Lanka: The Gem Island
An overview of the many types of gem-quality material, and its inclusions, currently found in Sri Lanka.
Heat Treating Ruby and Sapphire: Technical Aspects
A review of heat treatment methods available for use on natural or synthetic corundum.
Ruby and Sapphire from Muling, China
An emerging corundum deposit in northeastern China is discussed.
