J.S. Mason - Central Wales Orefield: Pyrrhotite

Pyrrhotite is very rare in Central Wales. These samples are from Erglodd mine and reveal the fresh mineral forming euhedral to subhedral brown aggregates in early galena, and its decay. Pyrrhotite decay is often quite impressive - the texture reminds me of the foliage hanging over a mangrove swamp. The only other pyrrhotite locality in Central Wales is Dylife mine, in the orefield's NE sector, where a few samples have been found over the years. Here, it forms part of the later mineralisation. With two, poorly understood and paragenetically different occurences, pyrrhotite in Central Wales will remain as a bit of an oddball.

Incidentally, pyrrhotite is a major and widespread sulphide in the pre-Acadian metalliferous vein suites of the Dolgellau Gold-belt and the Snowdon Caldera, both to the north of Central Wales.