Overview

Devilline is a relatively rare calcium-copper sulfate, CaCu4(SO4)2(OH)6·3H2O. It was named in 1872 by Félix Pisani in honor of Henri Étienne Sainte-Claire Deville (1818-1881) and its type locality is an unspecified site in Cornwall, England, UK. It mostly occurs as greenish, sky to light blue coatings and microcrystals. Specimens from the Špania Dolina are exceptional as devilline occurs here as very attractive bluish green rosettes up to 1 cm in diameter, consisting of individual platy crystals.

History

The discovery of this mineral at the Špania Dolina copper deposit in Slovakia has a rather interesting history, because the quality of the specimens from this locality was so good, that it was believed that it is a new mineral species different from devilline. The best specimens were collected in the 1879-1880 period. The first person who was attracted by this new find was Benjamín (Benő) Winkler (1835-1915) from Banská Štiavnica (Schemnitz, Selmeczbánya), who described it in his talk on April 16, 1879, as a new mineral and named it as urvölgyite after the Hungarian name of the type locality (Urvölgy). Just five days after Winkler´s description, famous Hungarian petrologist, prof. József Szabó (1822-1894) presented his description of the new find at the meeting of the Hungarian Academy of Sciences and also named this new mineral as urvölgyite. Szabó also included a detailed description of the find, including the very important note that the mineral was discovered in partly backfilled abandoned old tunnel and thus it is of post-mining origin. However, six days after Winkler's presentation about urvölgyite and only a day after prof. Szabó gave his description of urvölgyite, an article about a new mineral-herrengrundite from Špania Dolina, which is identical to Winkler´s and Szabó´s urvölgyite, was published by mineralogist Aristides Brezina (1848-1909) in Zeitschrift für Kristallographie und Mineralogie. Brezina named a new mineral after the German name of the type locality-Herrengrund and he was first who formally published a full description. Hence the name herrengrundite was valid for more than a 60 years, until 1940, when Austrian mineralogist Heinz Meixner (1908-1981) reestablished devilline as a valid species and confirmed by powder X-ray diffraction that devilline and herrengrundite are identical minerals.

Popularity

Devilline specimens from the Špania Dolina copper deposit in Slovakia are still considered as the best for the species in the world and are cherished by mineral collectors for their rarity, unusual bluish-green color and attractive form. Despite some new finds, fine old specimens of devilline from the Špania Dolina remain rare on the mineral market and are highly prized by mineral collectors.