Refractive indexes of over 4,000 recovered glass fragments were measured, with fragments selected using normal casework practices. A grouping method was applied to the data that yielded information on the number of matching and nonmatching glass types present on clothing. Proportions of matching and nonmatching glass were made for different clothing types and for different locations on clothing. Group sizes were also studied, and comparisons of refractive index distributions were made. It was not unusual to find large numbers of nonmatching glass fragments on clothing, although these were almost invariably from several different sources. The refractive index distribution of nonmatching glass on clothing was clearly different from that of control glass encountered in casework. Notes on caseworkers involved in collecting study data are appended. 7 references, 2 tables, and 14 figures