Search Result for "pitchstone": 
Wordnet 3.0

NOUN (1)

1. dark acid granitic glass; 



The Collaborative International Dictionary of English v.0.48:

Pitchstone \Pitch"stone`\, n. (Geol.)
   An igneous rock of semiglassy nature, having a luster like
   pitch.
   [1913 Webster]


WordNet (r) 3.0 (2006):

pitchstone
    n 1: dark acid granitic glass