Our Services Diamond Report Loose diamond grading, identity and quality observations. Natural Diamond Jewellery Report Natural diamond jewellery identification and mounted jewellery report. Laboratory Grown Diamond Jewellery Report Screening and reporting for laboratory grown diamond jewellery. Gemstone Report Gemstone species, variety, origin indicators and treatment observations. Gemstone Jewellery Report Mounted gemstone jewellery testing with report and article photograph. Moissanite Jewellery Report Identification and documentation for moissanite mounted in jewellery. Diamond and Gemstone Jewellery Report Combined analysis for diamond and gemstone jewellery pieces. Diamond Parcel Testing (Natural or Lab-Grown) Parcel screening for natural and laboratory grown diamond separation. Jewellery Marking Professional marking support for jewellery identification and traceability. Testimonials What People Say About Us Google Reviews Google Reviews ★★★★★ Loading live Google reviews... ‹ Loading Google reviews... › View / Write Google Review About TGL Professional Gemologist Welcome to TGL Gem Testing Laboratory Some facts about us Brands Working With