Uses a round brilliant cut diamond with three Excellent grades, the highest quality. Engraving: pt900, 0.232ct (center), serial number The carat weight of the side stones is also listed, but I couldn't quite read it. Size: 12.5 Comes with a Central Gem Laboratory appraisal report. I purchased this previously. The center diamond is of particularly high quality and is incredibly beautiful. I had the size adjusted to 12.5 at a jewelry store, but it no longer fits, so I've been keeping it in storage. I loved the slightly twisted design; it's cute. Thank you for looking.