Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Specimen Title
Wulfenite (w. azurite, malachite and copper arsenates)
Associated Minerals
arsentsumebite (?); azurite; bayldonite (?); gartrellite (?); smithsonite
Principal Mineral
Precursor Mineral
Size
Cabinet; 120mm
Location in the Mine
First oxidation zone
Provenance
Maucher, W.
Collection
NHM London; BM.1922,208
Entry Number
Specimen; TSNB828
Associated Minerals
arsentsumebite (?); azurite; bayldonite (?); gartrellite (?); smithsonite
Description
Localised groups of colourless-grey tablets of wulfenite (to 3 mm) on a cavernous matrix of powdery CuPb arsenates which includes pseudomorphs after wulfenite (to 5 mm) and (more sparsely) after mimetite. The matrix has not been analysed but arsentsumebite (?), bayldonite (?) and gartrellite(?) are likely components.
Pseudomorphs (and partial pseudomorphs) of malachite after azurite (to 5mm) forming groups (to 25 mm) are present on one face of the specimen (exhibits 1 and 2), while on the reverse side (Exhibit 3) unaltered azurite crystals are accompanied by sub-mm crystals of white smithsonite.
The specimen was purchased from Wilhelm Maucher (of Munich) in 1922 which dates it to 8 Level or above in the first oxidation zone. The fact that the Maucher and NHM labels highlight wulfenite (exhibits 4 and 5), when in fact wulfenite is a minor component of this paragenesis, is testament to the scarcity of this mineral in the upper levels of the mine.
