ISO 9001:2015
Verified feedback from jewelry houses, gemstone traders, and collectors across West Bengal and India who rely on our diagnostic certifications.
"Koustav Gemological Lab provides the most accurate and reliable gemstone testing in Nadia district. The instant QR verification gives our jewelry clients 100% confidence in purchasing natural blue sapphires and emeralds."
"Extremely thorough microscopic inclusion and specific gravity testing. Their certified reports clearly distinguish between unheated natural corundum and heat-treated stones. Top-tier scientific standard!"
"Fast 24-hour turnaround and the physical PVC cards are beautifully designed. The online report verification works flawlessly from any smartphone QR scanner. Highly recommended!"
"We send all our precious diamond solitaires and rubies to Koustav Lab for 4Cs grading. Their refractometer readings and fluorescence checks are always accurate and transparent."
"Honest, professional, and ISO 9001:2015 accredited. The staff at DL Roy Rd explains every diagnostic parameter patiently. Best gemological facility in the state."
"The tamper-proof security and detailed 14-parameter specification table give complete peace of mind when dealing with high-value natural Ceylon sapphires."