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Beryllium Diffusion of Ruby and Sapphire

The heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade.

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Ruby and Sapphire from Jegdalek, Afghanistan
Ruby and Sapphire from Jegdalek, Afghanistan

This study provides detailed mining and gemmological information on the Jegdalek deposit, in east-central Afghanistan, which is hosted by elongate beds of corundum-bearing marble.

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Sapphire and Garnet from Kalalani, Tanga Province, Tanzania

Located just 3 km south of the famous Umba locality, the geologically similar Kalalani area hosts deposits of gem-quality sapphire.

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Tairus Hydrothermal Synthetic Sapphires Doped with Nickel and Chromium

Researchers from the Tairus joint venture have developed the technology for the hydrothermal growth of gem-quality crystals of synthetic sapphire.

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Rubies and Fancy-Colour Sapphires from Nepal

Gem-quality rubies and fancy-colour sapphires have been recovered from dolomite marble lenses located high in the Himalayan mountains of east-central Nepal (Ganesh Himal).

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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.

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The Yogo Sapphire Deposit
The Yogo Sapphire Deposit

Yogo Gulch, discovered more than 100 years ago, is one of four major sapphire-producing areas in Montana, United States.

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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.

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Update on Diffusion-Treated Corundum: Red and Other Colours

Blue diffusion-treated sapphires have become a subject of considerable controversy since their introduction in significant quantities a few years ago.

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Sapphires from Changle in Shandong Province, China
Sapphires from Changle in Shandong Province, China

The fact that significant amounts of sapphire have been found in situ at Changle makes it unique among sapphire deposits in basaltic terrains around the world.

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