Copper staining.

Copper staining.

Hafod Feddgar mine, Central Wales orefield. The mine, having been closed for about 100 years, has given time for copper solution to stain leached calcite on the walls and floor of the adit. Not wishing to disturb the main body of interest, this specimen was taken from the floor close by. It is brecciated rock with precipitated calcite on the surface, coloured by copper solution leaching from the roof.