Epidote. 15 x 6 cm. Knappenwand, lower Sulzbach Valley in Salzburg, Austria. 1866.

Epidote crystals are rare and there are only a few occurrences of them world-wide. It was for this reason that Knappenwand in Salzburg attained world fame as a mineral deposit.

Epidote is a widely distributed rock-forming mineral. However, such free-standing, dark green, glossy, often bizarrely shaped crystals are found only seldom. In 1865 the alpine guide Alois Wurnitsch discovered several such epidote crystals in the lower Sulzbach Valley and sold them to a friend, a mineral dealer from Innsbruck. Around 1867 the latter started to excavate the site with paid laborers. After only three weeks, he stumbled on a deep crevice containing hundreds of epidote crystals. Although the best specimens were sold to buyers in Prague and Budapest, several exceptional pieces also reached the NHM. The world’s largest and finest epidote crystals were excavated at the Knappenwand site for over a century. Mining required both endurance and patience, as the tunnels were very inaccessible, and the parent rock – amphibolite – is one of the hardest rocks there is. Countless epidote crystals were destroyed between 1905 and 1920 by large-scale dynamiting, which apparently even shook the church tower in the distant village of Neukirchen. In 1977 the NHM leased the site, conducting a scientific research project there until 1992 to investigate mineral assemblages, formation conditions and rock packages. A total of 70 crevices in the epidote tunnels at Knappenwand were opened up in the process. This is why the mineralogical collection contains not only several particularly beautiful historical epidote crystals, but also several exceptional specimens from the more recent past.


  • Title: Epidote
  • Rights: (c) NHM (Lois Lammerhuber)

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