Amgueddfa Cymru - National Museum Wales

Lanthanite-(Ce)

Crystal System: Orthorhombic
Status of Occurrence: Confirmed Occurrence - Type Locality In Wales
Distribution: Rare
Chemical Composition: Cerium lanthanum neodymium carbonate hydrate
Chemical Formula: (Ce,La,Nd)2(CO3)3.8H2O
Method(s) of Verification: Britannia Mine - XRD & EMPA (University of Manchester).

Geological Context:

  • Supergene: post-mining oxidation & weathering deposits
SEM image of platy crystals of lanthanite-(Ce) coated by malachite from the type locality, Britannia Mine, Snowdonia, Gwynedd. Type specimen, National Museum of Wales Collection (NMW 84.6G.M.1). © National Museum of Wales.
Colourless platy lanthanite-(Ce) crystals coated with malachite. Field of view 7 mm wide. Type locality - Britannia Mine, Snowdon. National Museum of Wales Collection (NMW 84.6G.M.2). Photo D.I. Green, © National Museum of Wales.
Introduction: lanthanite-(Ce) is an extremely rare secondary mineral, named in 1985 as the cerium (Ce) end member of the lanthanite series. The type locality (first discovery) for lanthanite-(Ce) is Britannia Mine on Snowdon, where it was found in oxidized copper ore associated with weathered rare earth-bearing host rock. The type specimen is housed in the National Museum of Wales Mineral Collection (NMW 84.6G.M.1).
Occurrence in Wales: the extremely rare mineral lanthanite-(Ce) was first described by Bevins et al. (1985) from material collected from the walls of Sneyd's Level in Britannia Mine on Snowdon. The name lanthanite-(Ce) was chosen as this represents the cerium-predominant member of the lanthanite group. At Britannia Mine, lanthanite-(Ce) typically forms colourless, transparent plates with ragged terminations, associated with small malachite spheres. Exceptionally crystals reach 5 x 5 x 0.5 mm in dimension, but more typically are around 1 mm across. Lanthanite-(Ce) has since been recorded from a number of other localities worldwide, but remains exceptionally rare.

Key Localities:

  • Britannia Mine, Snowdonia, Gwynedd: colourless, transparent plates covered by radiating tufts of malachite, and associated with brochantite, posnjakite and chalcoalumite occur on the walls and the back of Sneyd's Level (Bevins et al., 1985).

There are no key localities for this specimen.

References:

  1. Bevins, R.E., 1994. A Mineralogy of Wales National Museum of Wales, Geological Series No. 16, Cardiff, 146pp.
  2. Bevins, R.E., Rowbotham, G., Stevens, F.S., Turgoose, S., & Williams, P.A., 1985. Lanthanite-(Ce), (Ce,La,Nd)2(CO3)3.8H2O, a new mineral from Wales, U.K. American Mineralogist, 70, 411-413.

There are no references for this specimen.