stranskiite

Stranskiite is a rare zinc-copper arsenate, described by Strunz (1960b) and named for Professor Ivan Nikolow Stranski (1897–1979), a German chemist and physicist, who performed pioneering work on crystal growth. The type specimen is from 30 Level in the second oxidation zone. Strunz was unable to provide PXRD data from the type material and, while stranskiite is an IMA-approved species, it has special project status (dated 1962; http://cnmnc.units.it/; accessed January 2023). The structure of stranskiite was refined by Plieth and Sänger (1965, 1967), with further revisions by Calvo and Leung (1969) and Keller et al. (1979c). Hänni et al. (1978) provided refined cell parameters and indexed PXRD data (Daltry 1992). Type material is conserved at the Institut für Mineralogie und Kristallographie, Technische Universität, Berlin (catalogue numbers 86/63, 86/64 and 88/14).

The type specimen for stranskiite was recovered from a depth of 1000 m below the surface (on 30 Level). It comprises a crust of radiating tabular crystals of cyan-blue stranskiite, individually to 11 mm, on chalcocite ore (https://www.ctms-jack.ch/list-of-minerals.html; accessed February 2023; Strunz 1960b).

Hänni et al. (1978) studied a specimen recovered (in 1976) from the East 9 Pillar on 31 Level. Here, the stranskiite occurred in massive tennantite ore (with minor galena) and was associated with olivenite, schultenite, zincolivenite "and others". This stranskiite had a lower Zn:Cu ratio than the type material and was used to provide refined cell parameters and indexed PXRD data as well as for single crystal diffractometry.

Keller and Bartelke (1982; page 145) included stranskiite as an early-formed mineral in the complex paragenetic sequence proposed for the minerals of the East 9 Pillar on 31 Level.

In 1994, stranskiite was discovered in the third oxidation zone, on 44 Level, as 2 mm sprays of white crystals on a blue unknown [GS 3 of Gebhard (1999)]. Gebhard (1999) suggested that the blue colour of the original stranskiite find may be atypical and that the white stranskiite (as found in the third oxidation zone) may be more common.

Stranskiite is readily confused with johillerite or ianbruceite.

arsenohopeite; calcioandyrobertsite; chalcocite; davidlloydite; galena; geminite; helmutwinklerite; hörnesite; ianbruceite; johillerite; koritnigite; köttigite; ludlockite; o’danielite; olivenite; prosperite; quartz; schultenite; tennantite-(Zn); warikahnite; zincolivenite; zincroselite