Welcome to GTLM – Trusted Gemmological Laboratory in India
GTLM is one of India’s most trusted gemmological laboratories, with branches in Rajkot, Bangalore, Mumbai, Pune, Delhi, and Hyderabad. Our certified gemologists use advanced technology to deliver precise and authentic reports for diamonds, gemstones, and jewellery. Every GTLM certificate reflects accuracy, integrity, and international standards.
Learn MoreDiamond & Gemstone Certification Experts
At GTLM, we specialize in grading and certifying loose diamonds and colored gemstones. Our reports cover cut, color, clarity, carat weight, treatments, and origin — providing complete transparency and trust for jewellers, traders, and collectors nationwide.
Learn MoreJewellery Reports & Bulk Certification Services
Whether it’s a solitaire ring, a designer necklace, or bulk gemstone lots, GTLM offers professional jewellery certification and bulk analysis services. Our detailed A3 and A4 report formats are tailored for exporters, retailers, and manufacturers who demand accuracy and credibility in every report.
Learn MoreGemstone Identification & Report
Accurate grading and identification of colored gemstones with detailed analysis of origin, treatments, and enhancements. Certified by GTLM experts using advanced gemmological instruments.
Diamond Report (Loose & Bulk)
Comprehensive certification for single and bulk diamond consignments with precise grading based on the 4Cs—Cut, Color, Clarity, and Carat Weight—ensuring complete confidence and transparency.
Gemstone Jewellery Report
Authentic certification for gemstone-studded jewellery with detailed evaluation of gemstone quality, treatments, and overall craftsmanship. Trusted by jewellers and exporters across India.
Diamond Jewellery A3 Report
Exclusive large-format A3 diamond jewellery certificates featuring high-resolution images, precise grading details, and professional presentation—ideal for exhibitions and retail display.
Verify Your GTLM Report
Accuracy and Integrity in Gem & Jewellery Certification
GTLM Lab stands as one of India’s most trusted gemmological laboratories, combining scientific precision with expert analysis. Using advanced instruments and international grading standards, we provide reliable certification for diamonds, gemstones, and fine jewellery.
- Comprehensive testing and grading of gemstones, diamonds, and jewellery.
- Accurate detection of treatments, enhancements, and origin analysis.
- Professional A3-size reports and bulk grading solutions for trade and retail.
With state-of-the-art laboratories in Rajkot, Bangalore, Mumbai, Pune, Delhi, and Hyderabad, GTLM delivers transparent and unbiased certification trusted by jewellers, exporters, and collectors across India. Every GTLM report represents precision, trust, and authenticity.
Our Features
GTLM Lab is equipped with state-of-the-art instruments and staffed by certified gemologists, delivering accurate, transparent, and internationally recognized reports for diamonds, gemstones, and jewellery.
Precise Gemstone Identification
GTLM Lab provides expert identification and classification of colored gemstones — natural, synthetic, or treated — ensuring complete accuracy and authenticity for market trust.
- Advanced spectroscopic, microscopic, and UV-visible analysis.
- Origin determination and treatment detection included in reports.
- GTLM certificates trusted by jewellers, investors, and gem traders across India.
Diamond Certification & Grading
GTLM Lab offers precise grading and certification for loose and bulk diamonds based on the 4Cs — Cut, Color, Clarity, and Carat Weight — following international standards.
Our detailed diamond reports empower jewellers, traders, and buyers with transparent documentation, ensuring confidence in every purchase or sale.
Gemstone & Diamond Jewellery Reports
Comprehensive certification for all types of jewellery — solitaires, designer pieces, and gemstone-studded ornaments — ensuring authenticity, quality, and transparency.
- Internationally recognized grading standards and formats.
- Complete reports ideal for retail, export, and professional display.
- Trusted documentation for jewellers and end customers alike.
Detailed A3 Diamond Jewellery Reports
GTLM’s exclusive A3 diamond jewellery reports provide large-format documentation with high-resolution images, diagrams, and comprehensive grading — perfect for retail, auctions, and exhibitions.
Recognized nationwide, GTLM’s A3 certificates set a new benchmark in diamond jewellery reporting, offering unmatched detail and presentation quality.