ISO 9001:2015 Certified Gemological Testing Laboratory DL Roy Rd, Near Krishnagar Municipality, Krishnagar, Nadia – 741101
+91 7548016604 info@koustav.com
Koustav Gemological Laboratory ISO 9001:2015
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DL Roy Rd, Near Krishnagar Municipality, Krishnagar
ISO 9001:2015 Certified Gemological Testing Center
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Frequently Asked Questions

Find quick answers to common inquiries regarding our testing methodologies, certificate verification, turnaround times, and pricing.

You can verify any issued certificate by visiting our Certificate Verification portal and typing in the Reference Number (e.g., GEM/06-2025/017), or by simply scanning the Digital QR Code printed on the certificate card with any smartphone camera.

Yes, 100% of our diagnostic procedures are non-destructive. We use optical refractometry, polariscopes, diffraction spectroscopy, UV fluorescence, and hydrostatic density balances that never scratch, heat, or damage your precious stones.

Our diagnostic reports include 14 distinct parameters: Reference Number, Date, Issued To, Physical Dimensions (mm), Weight (Ratti/Carats), Transparency, Color, Shape & Cut, Refractive Index (R.I.), Optic Character, Specific Gravity (S.G.), Microscopic Inclusions, Mineral Family, and Final Species Identification.

Standard turnaround is 24 to 48 hours. Same-day express testing is also available upon prior booking at our Krishnagar diagnostic center.

Yes. Using high-magnification darkfield microscopy and absorption spectroscopy, our certified gemologists can identify synthetic flux/flame fusion growth patterns, diffusion treatments, glass fillings, and thermal enhancements.

Our laboratory is located at DL Roy Rd, Near Krishnagar Municipality, Krishnagar City, Nadia, West Bengal - 741101. We are open Monday through Saturday from 11:00 AM to 6:30 PM (Sunday closed). You can reach us at +91 7548016604.