Wulfenite, Pb(MoO4, WO4) (Lead Molybdate), is a popular collection mineral because of its strong colours, bright luster and characteristic platy crystal habit. It was first discovered in 1785 by Xavier Wulfen who drew pictures of many prismatic and pyramidal crystals, before the importance of the shape of crystals in structure determination and mineral recognition was widely known.

Description: A dark brown earthy iron-rich matrix containing a small vug entirely filled with yellow-brown Wulfenite crystals. These are mostly small, but all show the platy habit described above. The largest crystal is about 5mm across and is an almost perfect prism, seen especially well from the side of the matrix. This is shown magnified on the photo. Underneath is a single deep-brown crystal which is twinned with a smaller example which emerges from one of the faces. Otherwise, the colour of the Wulfenite throughout the specimen is very rich and together with a bright waxy luster gives rise to a very good quality specimen of this mineral.

Location: Los Lamentos, Chihuahua, Mexico.