Violarite

Crystal System: Cubic
Status of Occurrence: Unconfirmed Occurrence
Distribution: Rare
Chemical Composition: Iron nickel sulphide
Chemical Formula: FeNi2S4
Method(s) of Verification: requires verification

Chemical Group:

  • Sulphides

Geological Context:

  • Supergene: in situ natural oxidation & weathering deposits
Introduction: violarite is a rare mineral which may occur as a product of initial supergene alteration of nickel ores (Arnold & Malik, 1974), where it replaces pentlandite. Some hypogene occurrences are also known.
Occurrence in Wales: the occurrence of violarite from Wales is based on visual identifications in polished sections of siegenite from the Central Wales Orefield (Rust & Mason, 1988). The probable violarite occurs as grainy, poorly-polished replacements of the cobalt pentlandite lamellae that commonly occur in siegenite grains and which alter rapidly relative to the siegenite. It is purplish-brown in polished section. Confidence on this identification is only moderate (J.S. Mason, unpublished data), and therefore analytical confirmation is required. The paragenetic setting is, however, appropriate for the presence of violarite.

Key Localities:

  • Esgairhir Mine, Tal-y-bont, Ceredigion: this mineral was reported by Rust & Mason (1988) on the basis of recent (at that time) optical observations of a replacement product of cobalt pentlandite lamellae in siegenite. Requires confirmation.

There are no key localities for this specimen.

References:

  1. Arnold, R.G. & Malik, O.P., 1974. Violarite in some nickel ores from Lynn Lake and Thompson, Manitoba, and Sudbury, Ontario, Canada. Canadian Mineralogist, 12, 320-326.
  2. Rust, S.A. & Mason, J.S., 1988. The minerals of Esgair-Hir mine, Dyfed, Wales. UK Journal of Mines & Minerals, 5, 35-43.

There are no references for this specimen.