Mimetite (w. goethite and smithsonite)

TSNB829
Specimen
Gregory & Co.Maucher, W.
Exhibit 1. Mimetite (w. goethite and smithsonite); 105 mm.
Exhibit 1. Mimetite (w. goethite and smithsonite); 105 mm.
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Exhibit 2. Specimen label (NHM London).
Exhibit 2. Specimen label (NHM London).
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
Exhibit 3. Specimen label (Maucher).
Exhibit 3. Specimen label (Maucher).
Image Credit: Malcolm Southwood photo; courtesy of the NHM London
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Specimen Title

Mimetite (w. goethite and smithsonite)

Associated Minerals

goethite; smithsonite

Principal Mineral

Mimetite

Size

Cabinet; 105mm

Location in the Mine

First oxidation zone

Provenance

Maucher, W.; Gregory & Co.

Collection

NHM London; BM.1924,571

Entry Number

Specimen; TSNB829

Associated Minerals

goethite; smithsonite

Description

A large, open vug in altered dolostone lined with a crust of rhombohedral smithsonite crystals which are in turn coated with dark brown goethite. Sheaves (to 10 mm) of sub-parallel, pale-yellow mimetite needles, some resembling bow-ties, are scattered on the goethite. An accompanying note records that there is minor substitution of phosphate (for arsenate) in the mimetite.


The specimen was purchased from J.R. Gregory & Co. in October 1924 (Exhibit 2), but with an older label from which the name of the dealer (Maucher) has been removed (Exhibit 3). The vintage of the specimen dates it unequivocally to the first oxidation zone.