noun[mass noun] Geology
A dull vitreous rock resembling hardened pitch, formed by weathering of obsidian.
More example sentences
- This feature was once described as ‘the finest ‘small’ mountain feature in the British Isles ’, and is in reality an east-west ridge of volcanic rock which appears as a narrow upthrust of columnar pitchstone when seen from the south or east.
- Similarly, Arran pitchstone has turned up in Ireland and Orkney, highlighting the complex exchange networks between these places.
- Also found was a flake of green Arran pitchstone, thought to be a waste fragment from the manufacture of a tool.
Definition of pitchstone in:
- The US English dictionary