In the deposits of New South Wales they are found associated with molybdenite in quartz gangue, in pipe-like deposits in granite.
The larger part of the world's production is from the molybdenite ores.
Wulfenite is rather common in the upper oxidized zone of deposits which contain lead minerals and molybdenite.
The chief ore minerals are molybdenite (molybdenum sulphide) and wulfenite (lead molybdate).
In molybdenite deposits secondary concentration has not been important.