WURTZITE

ZnS
Hexagonal

Wurtzite is an uncommon mineral locally and is known only from Sterling Hill. The most significant local occurrence was found at Sterling Hill in 1935 and has been called voltzite (Frondel, 1967).

Description

The original Sterling Hill wurtzite formed as botryoidal crusts and stalactitic masses and sheets with a solidified gel-like external flow texture. The color is dark brown to black; the luster is resinous in part, inclining to vitreous or dull; and the density is 3.48 g/cm³. A fibrosity is apparent and is normal to the specimen surface. Golden brown, hexagonal, 20-micron crystals were reported by Jenkins and Misiur (1994).

Composition

Wurtzite is a zinc sulfide mineral isostructural with greenockite. Frondel reported an analysis of wurtzite mixed with a zinc organometallic compound, finding zinc and sulfur, with an excess of oxygen, and carbon and hydrogen approximately 3.4 and 0.7 wt. %, respectively.

Occurrence and paragenesis

Sterling Hill wurtzite is best known from the occurrence of the mixture known as voltzite, which was found in the 2300 stope on the 1680 level. It occurred as an iridescent stalactitic mass, similar in shape to a wasp’s nest. The matrix is coarse-grained calcite with residual franklinite and local concentrations of pyrite and sphalerite. The innermost layers of the voltzite mixture give the X-ray data of sphalerite. This material was originally found in a watercourse which formed an aperture of a hundred feet of vertical extent. A more detailed description of voltzite, from Sterling Hill and other localities, is given by Frondel (1967).

Other specimens of Sterling Hill wurtzite are known; all are late-stage depositions in vugs and seams, and most have brown, lustrous to dull, botryoidal surfaces. An occurrence below the 700 level was reported by Jenkins and Misiur (1994). 

Copyright © 1995 by Pete J. Dunn			Website by Herb Yeates
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This page created: January 11, 2001