Crocoite - Encyclopedia

    Class : Sulphates, chromates, molybdates
    Subclass : Chromates
    Crystal system : Monoclinic
    Chemistry : PbCrO₄
    Rarity : Rare

Crocoite is a rare lead chromate, known in the oxidation zone of lead deposits, especially those located near ultrabasic chromium-rich rocks. Its name comes from the Greek krokos (saffron), because of its color. It appears in elongated to acicular prisms, sometimes hollow, with the faces of the prism often striated or grooved longitudinally. The crystals are frequently convex and sometimes take on a pseudo-octahedral appearance, but terminations are rare. Crocoite is transparent to translucent, with an adamantine luster. Its color is characteristic : vermilion red to bright orange-red, as well as its saffron streak and its high density of nearly 6. Its color fades to brick red in the light. This mineral is too rare to constitute a chromium ore, yet it was in the latter that it was discovered in 1797 by Vauquelin. Crystals are sought after by collectors.

In France, the lead vein of Nontron provided some small crystals (10 mm maximum) with pyromorphite.

No false recorded for this species.