Ex the collection of the Swiss collector Günther Hoppe. Via Rudolf Watzl, Mr Hoppe provided me with information that the piece had come from the Museum in Zwickau, which traded it in an exchange with Tilo Pönitz (http://www.mineralienwerkstatt.de/start.htm) in 2004. Mr Hoppe had acquired it from Peter Langsdorf of Potsdam and kept it for 15 years before selling it to Rudolf just before I acquired it from him in 2021. Rudolf featured the piece in his advertisement at p.158 in Volume 52 of The Mineralogical Record. Amongst the old labels for the specimen is one from Félix Pisani (1831 – 1920).

Photo by László Kupi