(Σωσθένης), a gem-engraver, for the above form, first suggested by Visconti, seems to be most probably the correct mode of reading the inscription on a celebrated gem, which others have read Sosicles or Sosocles. This is one of the many examples of the confusion of Greek names beginning in So. The Gem is an intaglio, representing a Gorgon's head, in that beautiful style which did not prevail until after the time of Praxiteles. (Stosch, pl. 65; Bracci, pl. 109; Mus. Borb. vol. iv. pl. 39; Eckhel, Pierres grav. 31 ; Lippert, Daktyliothek, 1.2.70-77; R. Rochette, Lettre à M. Schorn, pp. 154, 155, 2d ed.)
[P.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890