Legrandite

Legrandite


Composition: Zn2(AsO4)(OH).H2O
Crystal System : Monoclinic
Colours: Colourless, yellow, orange-yellow, blue
Lustre : Vitreous
Hardness (H) : 4.5
Specific Gravity (S.G) : 3.98

Distribution

Very rare. Second oxidation zone (31 Level). Third oxidation zone, (notably on 44 Level).

Occurrence

  • Supergene
  • 2nd Oxidation Zone
  • 3rd Oxidation Zone

Notable Finds

Outstanding specimens were obtained from the "Zinc Pocket" on 44 Level, discovered in 1992.

Paragenetic and General Notes

Legrandite was first encountered in the second oxidation zone on 31 Level in March, 1978, as brilliant orange-yellow radiating masses, with single crystals (to nearly 10 mm), associated only with smithsonite (Keller and Bartelke, 1982). 

In the third oxidation zone, a small number of outstanding specimens were recovered from the so-called "Zinc Pocket" on 44 Level (Gebhard, 1999).  These specimens included terminated crystals (to 20 mm) some of which are associated with reinerite, white adamite, paradamite, and leiteite.

A dark-blue variety of legrandite has been provisionally identified, accompanying ianbruceite, as inclusions in leiteite from 44 Level. (Bill Pinch. personal communication to M.Southwood, February 2015).