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”

In 1999, we were the first laboratory to implement qualitative grading (clarity, colour, symmetry, polish, girdle thickness, etc.) of melee diamond batches for the Swiss fine watchmaking industry. 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.

Fancy diamond

We issue grading and testing reports for fancy diamonds of all hues — yellow, pink, blue, green, orange, red, and beyond. Determining the origin of colour is one of the most complex and critical assessments in gemmology, as it distinguishes natural from treated or synthetic stones. Our reports mention authenticity, colour origin, and clarity treatment, in compliance with the highest international standards.

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.

GGTL Laboratories Switzerland is specialized in the identification of biogenic materials and their species. We are permanently surveying species taxonomy and carrying out scientific research on these materials in order to increase our understanding and their identification, so our reports are in compliance with the CITES legislation. Our expertise covers a wide range of biogenic materials, including corals, pearls, wood, amber, and tortoiseshell.

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.

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.