Check for a certification from a reputable gemological lab
Use a jeweler’s loupe to inspect for natural inclusions
Look for sharp facet edges and precise craftsmanship
Test the fog effect by breathing on the stone
Check how the stone reflects light and sparkles
Use the water test to see if it sinks quickly
Examine the setting and mounting for quality
Try the newspaper or text test through the stone
Use a thermal conductivity diamond tester
Compare the stone’s weight and size to known diamonds
Have a professional jeweler inspect it
Check for laser inscriptions on the girdle
Look for signs of double refraction in the stone
Test under UV light for fluorescence
Verify the seller’s return policy and documentation