Duftite after mimetite (w. azurite)

TSNB717
Specimen
Palache, C.
Exhibit 1. Duftite after mimetite (w. azurite); 50 mm.
Exhibit 1. Duftite after mimetite (w. azurite); 50 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. 16 mm field of view.
Exhibit 3. 16 mm field of view.
Image Credit: Malcolm Southwood
Exhibit 4. 14 mm field of view.
Exhibit 4. 14 mm field of view.
Image Credit: Malcolm Southwood
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Specimen Title

Duftite after mimetite (w. azurite)

Associated Minerals

bayldonite; azurite; duftite

Principal Mineral

Duftite

Precursor Mineral

Mimetite

Size

Miniature; 50mm

Location in the Mine

First oxidation zone

Provenance

Palache, C.

Collection

MGMH; 96946

Entry Number

Specimen; TSNB717

Associated Minerals

bayldonite; azurite; duftite

Description

A mixed Cu/Pb arsenate matrix (not analysed) hosting pseudomorphs and epimorphs of duftite (EDS confirmed) after mimetite (to 4 mm; exhibits 2 and 3) and, separately, bayldonite (EDS confirmed) after mimetite (Exhibit 4). The duftite has in turn been partly encrusted with a chalky white substance which also has a composition consistent with bayldonite (EDS indicated). Lustrous, prismatic crystals of azurite (to 15 mm) complete the paragenesis.


SEM/EDS analysis of the duftite replacing mimetite conducted by Martin Števko (Slovak Academy of Sciences, Bratislava, Slovakia); SEM/EDS analysis of the bayldonite by Frank Keutsch (Harvard University).


The specimen is from the collection purchased by Charles Palache during his visit to Tsumeb in April 1922, which dates it to the upper part of the first oxidation zone (i.e. 8 Level or above).