The subjects are azurite, copper, variscite and wulfenite.
Occurrences of wulfenite are numerous, but none are of economic importance.
British Dictionary definitions for wulfenite
a yellow, orange, red, or grey lustrous secondary mineral consisting of lead molybdate in the form of platelike tetragonal crystals. It occurs with lead ores and is a source of molybdenum. Formula: PbMoO4
C19: from German Wulfenit, named after F. X. von Wulfen (1728–1805), Austrian mineralogist