Diamond ring d0.308ct means that the weight of the diamond on the diamond ring is 30.8 cents, D is the abbreviation of diamond, ct is the abbreviation of carat, 0.308ct is 0.308 carat, one carat is equal to 100 cent, and 0.308 carat is what we usually call 30.8 cents.

I hope I can help you. If you have any questions, please ask. If you are satisfied, please adopt it!