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Spiral structure in a Colombian emerald
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
Publication

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
Publication

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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Brown Diamond
Insight

Webinar: Brown diamonds - A new in-depth look at their properties and classification

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1K followers on Instagram
Insight

1K followers on Instagram

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Tiny guest oriented inclusions with biotite crystal inclusions in a peridot from Myanmar
Micrographs

Tiny guest oriented inclusions with biotite crystal inclusions in a peridot (forsterite) from Myanmar

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Melee-sized coloured sapphires
Publication

Efficiently Testing Melee-Sized Coloured Stones

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Welcome sign and Mogok seen from the view point.
Insight

Mogok : The Valley of Precious Stones

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