Wulfenite mineral. The mineral wulfenite is a lead molybdate (Pb.Mo.O4). It is a secondary mineral, usually found associated with lead ores in the oxidized zone of lead-bearing rocks. Wulfenite crystallizes in the tetragonal system and most typically occurs in sharp, thin tabular crystals that range in colour from orange-red to yellowish-orange. This sample, from the Kuruktag Mountains in Urumqi, northern China, is 22 centimetres across.