Home > Lead Minerals – December 31 > MS1163 Mimetite after Cerussite

Mimetite after Cerussite - Sold

Mimetite is a lead arsenate chloride, a member of the apatite group. The mineral name derives from the word mimic, since the mineral impersonates pyromorphite. This is a classic Tsumeb specimen, consisting of bright yellow needles of mimetite which have replaced cerussite twins. In this example, the replaced cerussite sixlings are rather equant, without obvious re-entrant angles, reaching 1.8 cm across. These pseudomorphs from Tsumeb form as mimetite encrusts cerussite, and subsequent gradual removal of cerussite occurs with periodic infilling of further mimetite. Consequently, these pseudomorphs have spongy cores, internally showing concentric layers of mimetite. Perhaps this indicates pulsing of arsenate rich fluids... A great example of a curious lead mineral pseudomorph.