Duftite after mimetite (w. smithsonite and cerussite)

TSNB768
Specimen
Klein, W.
Exhibit 1. Duftite after mimetite (w. smithsonite and cerussite); 61 mm.
Exhibit 1. Duftite after mimetite (w. smithsonite and cerussite); 61 mm.
Image Credit: Malcolm Southwood
Exhibit 2. 22 mm field of view.
Exhibit 2. 22 mm field of view.
Image Credit: Malcolm Southwood
Exhibit 3. BSE image showing compositional zoning in duftite with darker zones Ca-bearing and lighter zones closer to end-member composition. 100 µm scale bar on image.
Exhibit 3. BSE image showing compositional zoning in duftite with darker zones Ca-bearing and lighter zones closer to end-member composition. 100 µm scale bar on image.
Image Credit: Martin Števko
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Specimen Title

Duftite after mimetite (w. smithsonite and cerussite)

Associated Minerals

cerussite; smithsonite; undetermined

Principal Mineral

Duftite

Precursor Mineral

Mimetite

Size

Cabinet; 61mm

Location in the Mine

First oxidation zone; Open Pit

Provenance

Klein, W.

Collection

MGMH; 127423

Entry Number

Specimen; TSNB768

Description

A vug in oxidised sulphide ore hosts hollow epimorphs of duftite (EDS verified) after mimetite. Partly overgrowing the epimorphs are crystals of pale green smithsonite, possibly coloured by underlying (or included) duftite, and colourless-white cerussite, including crystals located on the tips of the arsenate epimorphs.


SEM/EDS analysis (Martin Števko; Slovak Academy of Sciences, Bratislava, Slovakia) has shown that the replacing arsenate is duftite, compositionally zoned, ranging from near end-member to Ca-rich (Exhibit 3).


The specimen was number 455 in the collection of Wilhelm Klein, production manager at Tsumeb between 1916 and 1939. His handwritten catalogue attributes the specimen to the Open Pit.