Source : Webster's Revised Unabridged Dictionary (1913)

Tremolite \Trem"o*lite\, n. [From Tremola, a valley in the Alps,
   where it was discovered.] (Min.)
   A white variety of amphibole, or hornblende, occurring in
   long, bladelike crystals, and coarsely fibrous masses.

Source : WordNet®

tremolite
     n : a white or pale green mineral (calcium magnesium silicate)
         of the amphibole group used as a form of asbestos