aurichalcite

TSNB36
Mineral
First oxidation zoneSecond oxidation zone (?)Supergene
Aurichalcite: Pale greenish-blue acicular crystals (to 1.5 mm) associated and intergrown with hemimorphite and hydrozincite. 30 mm field of view. MGMH Collection. 2022.4.5815L.
Aurichalcite: Pale greenish-blue acicular crystals (to 1.5 mm) associated and intergrown with hemimorphite and hydrozincite. 30 mm field of view. MGMH Collection. 2022.4.5815L.
Image Credit: Malcolm Southwood

Mineral Species

aurichalcite

Type Locality

No

Composition

(Zn,Cu2+)5(CO3)2(OH)6

Crystal System

Monoclinic

Status at Tsumeb

Confirmed

Abundance

Somewhat rare

Distribution

First and second (?) oxidation zones

Paragenesis

Supergene

Entry Number

Species; TSNB36

General Notes

Aurichalcite was relatively common in the upper portion of the first oxidation zone and particularly so in the open pit workings. It is, however, a very rare mineral at depth and its occurrence in the deeper oxidation zones is not unequivocal.


In the near-surface environment aurichalcite occurred in a distinctive paragenesis with hemimorphite and hydrozincite (Maucher 1908a,b; Gebhard 1999). Less commonly, it has been found associated with smithsonite. Typically, it occurs as pale green to sky-blue and turquoise-blue acicular crystals and crusts (Pinch and Wilson, 1977).

Pseudomorphs

Aurichalcite has been reported to form pseudomorphs after azurite (rare; Weber, 1977).