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