SINGLE DIAMOND

We issue grading and testing reports for D-Z colourless diamonds of any type (IIa, Ia, IIb, etc.) as well as for fancy coloured diamonds and even the complicated green diamond. Our reports mention authenticity, clarity treatment, and colour origin (whenever relevant and possible). 

Diamond parcels “melee”

Our melee diamond services can contain the 4cs. They include authenticity and treatment for colourless diamonds and colour origin reports for coloured diamonds. These services are available for melee of any size and shape.

Diamond Jewellery 

The setting of a diamond is no barrier to us. We offer authenticity reports for any piece of diamond jewellery, no matter the colour, shape or size. If you wish to know more about the mounted diamond, un-setting may be required for further testing.

Single gem

From the most common to the most curious, our expert gemmologists will analyse any gemstone and biogenic material. Not only will we identify the material but also the treatment and geographical origin, whenever possible.

Small calibrated / melee gems

The certification of coloured melee size gems from 0.4 to 3.7 mm will mention authenticity as well as treatment and origin, whenever possible.

Gem Jewellery

Any piece of jewellery or object set with gemstones or biogenic material can be identified and certified at GGTL Laboratories. Our reports will mention the treatment and geographical determination, whenever possible.

We offer pearl reports for both cultured and natural, nacreous and non-nacreous pearls. Any treatment will be unveiled and, whenever possible, the mollusc species will be mentioned.