News

Spiral structure in a Colombian emerald
High-temperature heated blue sapphire from Sri Lanka
Micrographs

High-temperature heated blue sapphire from Sri Lanka

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A "Maltese Cross" pattern seen in a natural diamond viewed with GGTL DFI System
Insight, Micrographs

A "Maltese Cross" pattern seen in a natural diamond viewed with GGTL DFI System

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Naturally healed fracture, with residual liquid film and negative crystal with altered inclusion in a purplish red sapphire from Sri Lanka
Micrographs

Naturally healed fracture, with residual liquid film and negative crystal with altered inclusion in a purplish red sapphire from Sri Lanka.

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The heat treatment of corundum at Moderate temperature
Micrographs, Research

The heat treatment of corundum at Moderate temperature

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Turquoise crystals, Beauvoir, Echassière, Ebreuil, Allier-Auvergne, France
Micrographs

Turquoise crystals, Beauvoir, Echassière, Ebreuil, Allier-Auvergne, France

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GGTL Certificates
Insight

From now, all GGTL reports will be exclusively in English.

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Precious corals, C. rubrum, P. elatius, C. japonicum, C. konojoi, H. laauense, Coll. SGDF, Photograph M.Rondeau
Research

Review and update of the classification of precious corals.

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Dendritic inclusions (mode of formation unknown) in an unheated dark blue magmatic-related sapphire
Micrographs

Dendritic inclusions in an unheated magmatic-related sapphire from Attapeu province, South Laos

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Bubbles in brownish epoxy resin in an emerald from Colombia, darkfield illumination
Micrographs

Emerald from Colombia whose cracks are filled with epoxy resin

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New Large Black Synthetic Moissanite as a Black Diamond Imitation
Research

New Large Black Synthetic Moissanite as a Black Diamond Imitation

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Blue anatase crystals in quartz from Brazil
Micrographs

Blue anatase crystals in a quartz from Brazil

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CO2 diamond slice, SGDF-5864, under UV excitation (220 nm). Micrograph Dr. T. Hainschwang
Insight

Conference on replay: Brown Diamonds, a new in-depth look at their properties and classification

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