Image Credit: Malcolm Southwood
Image Credit: Malcolm Southwood
Image Credit: Malcolm Southwood
Image Credit: MGMH Archive
Specimen Title
Malachite after azurite
Associated Minerals
smithsonite
Principal Mineral
Precursor Mineral
Size
Cabinet; 68mm
Location in the Mine
First oxidation zone
Provenance
Palache, C.
Collection
MGMH; 87485
Entry Number
Specimen; TSNB683
Description
A single composite crystal of azurite (55 mm), tabular and elongated, with the termination replaced by malachite, on a shard of pale green smithsonite (exhibits 1-3).
This specimen is figured in the azurite monograph of Palache and Lewis (1927) as their figure 34, which included both a monochrome photograph and a line drawing (Exhibit 4) to illustrate the process by which malachite replaces azurite. Their accompanying note reads: "The malachite fibers radiate from one important center on the front pinacoid, and many interfering centres on the prism, giving a confused network of interwoven splendant fibers. The front of the invading malachite is roughly concentric normal to the fibers…".
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).
Exhibit 4 is a scan of the original line drawing submitted pre-publication for the Palache and Lewis (1927) azurite monograph.
