Look for a laser inscription on the girdle
Use a jeweler’s loupe to inspect clarity and inclusions
Check for a certification report from a reputable lab
Test thermal conductivity with a diamond tester
Observe sparkle and light performance under strong light
Check for fogging by breathing on the stone
Inspect facet edges for sharpness and wear
Compare weight and size against known diamond measurements
Use UV light to check fluorescence
Have a professional gemologist verify the stone