Here is a spectacular wulfenite specimen on limonite from a recent find at Mapimi. The crystals are exquisite: they are exceptionally sharp, transparent windowpanes, mostly about 4 mm and extremely sharp.  They are less than 1 mm thick, with razor sharp corners and beveled edges. All the surfaces are smooth and highly reflective.  The wulfenite sits on some nice green mimetite, which adds color and contrast.