14-karat gold. Round Brillian-cut Diamond = approximately 0.25 ct. tw.; color = H-I; clarity = SI-I. Approximately 18in long. It is customary to treat most gemstones to achieve enhanced color and durability. Some of these treatments may not be permanent, and may require special care.. Please note: In product titles ct. tw. refers to the total carat weight of all diamonds and/or gemstones combined.. Choose from the following:. 14-karat rose gold. 14-karat white gold. 14-karat yellow gold.