In appearance silver presents a pure white colour with a perfect metallic lustre. It is the most malleable and ductile of all metals with the exception of gold. Silver occurs in nature in ores and as a free metal; the chief ores are sulphides, from which the metal is extracted by smelting with lead. It has been mined since prehistory. Digital photography, has lead to the decline of a major traditional market for silver. At the same time global demand for silver remains high, for example in lead-free solder.