Solfatares and sulphur deposits on Namafjall, site of a major Medieval sulfur mine, Iceland.

Solfatares and sulphur deposits on Namafjall, site of a major Medieval sulfur mine, Iceland.

The Krafla area is well known as one of the most active volcanic zones in Iceland. Namafjall is a mountain 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 crust that emit hydrogen sulphide ( and other gasses) which, in contact with oxygen, turns into elemental sulphur and sulphur dioxide. It has been mined in parts of Iceland since the 13th century and only ceased production in the 19th century.