: For qualifying loose diamonds priced $500 and above , eBay provides a free authentication service where the stone is sent to GIA (Gemological Institute of America) experts for verification before reaching you.

: For items between $200–$499 , buyers can often pay a $40 fee at checkout to include this service.

: Must be natural or lab-grown, colorless (D–Z range), and at least 0.15 carats .