During the Neolithic period in Europe certain outcrops of fine-grained rock were exploited for the production of polished axes. Microscopic analysis of the rock allows the sources to be identified, as each type of rock has its own distinctive crystalline structure; this enables the trading networks to be reconstructed. In the British Isles important factories have been identified at Great Langdale, Graig Llwyd, Penwith and Tievebulliagh.
The Macmillan dictionary of archaeology, Ruth D. Whitehouse, 1983Copied