Carat may be the unit of measurement used to find out the weight to a diamond. One carat is equal to 200 milligrams and it is divided in to 100 points, so a half-carat diamond would be equivalent inside 50 points. The larger the carat sized, the more valued and expensive the diamond becomes.When shopping for a diamond, it is important to do your research and be savvy about finding the best deals. One insider key try to consider buying a diamond slightly below the traditional carat weights, particularly 0.9 carats instead of 1.0 carats.