Abstract

Color and clarity are two of the attributes that give gemstones used in jewelry value. Gemstones deficient in either color or clarity can be enhanced. Almost worthless material can at times be converted into valuable-appearing gemstones. An estimated two-thirds of all colored gemstones used in jewelry have been treated. Accordingly, the identification of the use of treatments and the disclosure of enhancements to the purchaser are important.

Some treatments are practiced so widely that untreated material is essentially unknown in the jewelry trade. The heating of pale Fecontaining chalcedony to produce red-brown carnelian is one of these.

The stability of a particular treatment is also important. The enhancement should survive during normal wear or display conditions.

Heat and irradiation treatments are the major processes to enhance gemstones. A trained gemologist, is needed for identification of treated gems.