A technique of enhancing or neutralizing a gemstone's color. Enhancing a gemstone involves painting the pavilion facets of the stone to improve its color. Neutralization is used to tone down the yellow of a diamond. This is done by painting violet dye around the girdle of a diamond (or also the pavilion facets). It has been used since the 16th century, even prior to the origin of the brilliant cut. Tinted gemstones are usually set in a closed setting to hide the fact that the stones have been altered.