Chrysocolla is a hydrated copper phyllosilicate mineral which can occur in the oxidation zone of copper ore deposits. The small pieces shown here were collected from the floor of an adit in the Hafod feddgar mine in central Wales. Dr. Stephen Plant of the Russell society is shown inspecting the deposit which has accumulated on walls and floor in the hundred years or so since the mines closure. Care was taken not to touch the main deposits in the mine.