Check for a laser inscription on the girdle
Look for a grading report from a reputable lab
Use a jeweler’s loupe to inspect for natural inclusions
Test the stone’s fog dissipation
Check for strong sparkle and light return
Use a diamond tester
Compare thermal conductivity with a thermal probe
Inspect the setting and mounting quality
Look for sharp facet edges and precise symmetry
Verify the stone with a professional jeweler
Check whether it scratches glass
Observe if it is too perfect and flawless
Examine under UV light for fluorescence
Test for double refraction in certain simulants
Weigh and measure it against known diamond proportions