azurite

TSNB682
Specimen
Palache, C.
Exhibit 1. Azurite; 51 mm.
Exhibit 1. Azurite; 51 mm.
Image Credit: Malcolm Southwood
Exhibit 2. 25 mm field of view.
Exhibit 2. 25 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. Crystal drawing (Palache and Lewis 1927).
Exhibit 4. Crystal drawing (Palache and Lewis 1927).
Image Credit: MGMH archive
Exhibit 5. MGMH87484d. Goniometer mount in a glass phial; 70 mm.
Exhibit 5. MGMH87484d. Goniometer mount in a glass phial; 70 mm.
Image Credit: Malcolm Southwood
Thumbnail by 1Thumbnail by 2Thumbnail by 3Thumbnail by 4Thumbnail by 5

Specimen Title

azurite

Associated Minerals

arsentsumebite (?); gartrellite (?); malachite

Principal Mineral

Azurite

Size

Cabinet; 51mm

Location in the Mine

First oxidation zone

Provenance

Palache, C.

Collection

MGMH; 87484b

Entry Number

Specimen; TSNB682

Description

Azurite crystals (to 6 mm), mostly lustrous and unaltered, but with one group extensively replaced by malachite (Exhibit 2). These crystals rest on a matrix of green and yellow Cu/Pb arsenates – possibly arsentsumebite (?) with subordinate gartrellite (?), although these are not verified – which also appear to be partly pseudomorphous after an undetermined precursor.


The specimen is of historical interest because it was figured in the azurite monograph of Palache and Lewis (1927; their figure 29) to illustrate their "Type 12" azurite habit from Tsumeb (Exhibit 3), which they described as: "…tabular parallel to the base … with c [(001)] dominant and m [(110)] and h [(221)] prominent…" with other forms present: 𝜎 (101), 𝜙 (201), 𝑙 (023), f (011), p (021) and λ (-2 18 3) (Exhibit 4).


Exhibit 5 shows a crystal from this specimen mounted for measurement on the goniometer by the authors of the 1927 azurite monograph, Charles Palache and Lyman Lewis.


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).