Gems & Gemology, Summer 1989, Vol. 25, No. 2
The Characteristics and Identification of Filled Diamonds
John I. Koivula, Robert C. Kammerling, Emmanuel Fritsch, C. W Fryer, and David Hargett, and Robert E. Kane
The filling of surface-reaching cleavages, fractures, and other separations in diamonds has generated a great deal of concern during the last two years. This article reports on the study of six diamonds both before and after a filling treatment and the examination of 12 additional filled stones. Microscopy provides the best means of identifying that a stone has been filled. Chemical and other analyses indicate that the filling material is a type of glass. The filling will not withstand all standard jewelry manufacturing and repair procedures.