CERTIFICATION
Certification is the main facility at GTL, which broadly issues two types of reports
– identification and diamond grading. Each and every stone under test is examined
by two or more gemmologists / graders independently, first using the standard gemmological
equipment, and then by scientific methods using sophisticated spectrometers. Therefore,
every report issued is based on vast gemmological experience of the gemmologists
/ graders along with scientific facts. The report format however varies depending
on the type of category under which the certification has been carried out.
Identification reports are issued for gems in following whichever form:
- Loose Rough – well-formed crystals or broken, with or without a polished surface,
transparent to opaque,
- Loose Cut in any style – pre-form, faceted, cabochon, bead - drilled /undrilled
- Set in jewellery / in a decorative piece - open or close back setting
- Carvings
- Beads strung on a thread / wire
Testing is carried out by following the pre-determined criteria strictly, although
the tests to be performed largely depend on the form in which the gem is submitted
for identification. GTL classifies the gems and minerals on the basis of group/species/variety
where applicable, based on the nomenclature guidelines drawn by the CIBJO, the World Jewellery Confederation
Enhancements / Treatments are routinely mentioned at no additional charge subject
to their identification with the available techniques at GTL Jaipur and significance
of disclosure it carries. Various treatments include coating, foiling, diffusion,
lasering, coloured impregnation, all various treatments in corundum (including heat,
diffusion, fillers, etc.), fracture filling along with the nature of filler and
its quantification in emeralds, irradiation / heating in diamonds is reported on
the GTL Identification reports.
For grading reports all diamonds are graded for 4 C (cut, clarity, colour and carat
weight) quality grading as per well-established international criteria, while in
mounted diamonds ‘cut’ is replaced by ‘quality of finish’.
SINGLE STONE IDENTIFICATION REPORT
LOT IDENTIFICATION REPORTS
JEWELLERY REPORT
DIAMOND GRADING REPORT
DISCLOSURE POLICY