Solfatares and sulphur deposits, Namafjall, Iceland. Namafjall is a mountain in an area of the active volcanic zone of Northern Iceland. It is covered in sulfur which was mined from Medieval times. Sulphur is a chemical element (symbol S) which occurs in two forms but in Iceland, only elemental sulphur is found. Solfatares, openings in the Earth's crust, emit hydrogen sulphide (and other gasses) which, in contact with oxygen, turn into elemental sulphur and sulphur dioxide. It was mined in parts of Iceland since the Middle ages for the manufacture of gunpowder and only ceased production in the 19th century.