After a gemstone has been cut and polished, the final carat weight that remains is expressed as a percentage of the weight of the original uncut rough gem. The less wastage, the higher the yield is said to be. Lapidarists take different approaches to different gemstones. For example, large opaque gemstones are often cut to maximise carat weight, whereas gems that have strong brilliance and dispersion should be cut to maximise the gem’s beauty.
Unfortunately, today, we all too often see gems that are cut so as to reach certain rounded carat weights, rather than to truly unveil the beauty of the gem. When buying gems such as Tanzanite and Paraiba, be sure to check the quality of the cutting, especially if its weight is marginally over a rounded carat weight.
