malachite after azurite

TSNB687
Specimen
Palache, C.
Exhibit 1. Malachite after azurite; 90 mm.
Exhibit 1. Malachite after azurite; 90 mm.
Image Credit: Malcolm Southwood
Exhibit 2. 45 mm field of view.
Exhibit 2. 45 mm field of view.
Image Credit: Malcolm Southwood
Thumbnail by 1Thumbnail by 2

Specimen Title

malachite after azurite

Associated Minerals

azurite; goethite; smithsonite (?); undetermined

Principal Mineral

Malachite

Precursor Mineral

Azurite

Size

Cabinet; 90mm

Location in the Mine

First oxidation zone

Provenance

Palache, C.

Collection

MGMH; 87508

Entry Number

Specimen; TSNB687

Description

Sharp pseudomorphs of malachite after prismatic, terminated azurite crystals (to 35 mm) in a vug in gossanous matrix (goethite) that includes a 25 mm fragment of altered dolostone, massive malachite, unaltered azurite and some cryptocrystalline greenish-yellow arsenates (undetermined). Between the pseudomorphs on the display face are radiating sprays of composite, colourless, acicular smithsonite crystals with reddish-brown tips, presumably due to iron staining (Exhibit 2).


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