borosilicate

from WordNet (r) 3.0 (2006)

borosilicate
    n 1: a salt of boric and silicic acids

from The Collaborative International Dictionary of English v.0.48

Borosilicate \Bo"ro*sil"i*cate\, n. [Boron + silicate.] (Chem.)
   A double salt of boric and silicic acids, as in the natural
   minerals tourmaline, datolite, etc.
   [1913 Webster]