Molybdenite is the principal ore mineral of molybdenum and rhenium. It occurs widely in igneous and metamorphic rocks generated under high temperature conditions. Despite its lack of popularity and rare crystal forms, it is a very interesting and important industrial mineral.
Crocoite is a rare lead and chromium secondary mineral. Its rarity, bright red color, and exceptional crystal forms have guaranteed its place as a prized collection mineral. Crocoite is the first historic source of chromium and natural yellow pigment - unfortunately highly toxic.
Wulfenite is a mineral species composed of lead molybdate, Pb(MoO4), sometimes occurring in sufficient abundance to be mined as an ore of lead, but in practice its molybdenum content is greater. Even so, it is rarely used as an ore mineral because there are easier sources of lead or molybdenum available to exploit.
Stibnite is the principal ore of antimony. The mineral is widely admired for its spectacular crystalline habits, which exhibit extremes of sharpness, luster and size. Its principal metallic component, antimony, probably received its name from the Greek anthemon, describing its flowery appearance in clusters. The Latin name for the mineral, stibium, survives today as stibnite.