austinite (w. dolomite)

TSNB459

Specimen

Exhibit 1. Austinite (Cu-riich, w. dolomite); 55 mm.
Exhibit 1. Austinite (Cu-riich, w. dolomite); 55 mm.
Image Credit: Malcolm Southwood
Exhibit 2. 35 mm field of view.
Exhibit 2. 35 mm field of view.
Image Credit: Malcolm Southwood
Exhibit 3. Analytical data; austinite. (M. Southwood and P. Carr; unpublished).
Exhibit 3. Analytical data; austinite. (M. Southwood and P. Carr; unpublished).
Image Credit: Malcolm Southwood
Exhibit 4. Analytical data. Analyses for this specimen (blue circles) indicate compositions corresponding to austinite, Cu-bearing austinite, and Pb- and Zn-bearing conichalcite.
Exhibit 4. Analytical data. Analyses for this specimen (blue circles) indicate compositions corresponding to austinite, Cu-bearing austinite, and Pb- and Zn-bearing conichalcite.
Image Credit: Malcolm Southwood
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Title

austinite (w. dolomite)

Principal Mineral

Austinite

Size

Cabinet; 55mm

Collection

Southwood, M. MS2010.126

Provenance

Grosch, K.; Bruce, I.

Entry Type

Specimen TSNB459

Description

A vuggy matrix of dolostone hosts glassy rhombohedral dolomite crystals which are extensively overgrown by coarsely crystalline austinite crystals (to 1 mm). The austinite crystals are blocky to prismatic in habit with chisel-shaped terminations (Exhibit 2).

Electron microprobe (WDS) analysis has confirmed that much of the austinite is of near end-member composition (exhibits 3 and 4), but with significant variation; zones corresponding to Cu-bearing austinite and Pb-Zn-bearing conichalcite are also present; the mean composition (Exhibit 3) corresponds to a Cu-rich austinite.

The specimen was aquired in 2010 from Ian Bruce who was dispering the collection of Karl-Heinz Grosch. The location in the mine is not recorded.

Associated Minerals

conichalcite; dolomite