The Collaborative International Dictionary of English v.0.48:

Strass \Strass\, n. [So called from its inventor, a German
   jeweler: cf. F. stras.] (Chem.)
   A brilliant glass, used in the manufacture of artificial
   paste gems, which consists essentially of a complex
   borosilicate of lead and potassium. Cf. Glass.
   [1913 Webster]