A culet (also known as a rib ) is the tiny facet with which a gemstone cut to a diamond ends at the lower end. This prevents the stone from splitting at this fragile point. The eight facets of the lower part can also converge to form a point . A gemological report on a diamond then contains the information “culet not present” or “no culet”. A point increases the value of the diamond, a large culet decreases it.