Walchowite

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Walchowite is a cretaceous mostly yellowish fossil resin ( retinite ), which was found in lignite not far from the place Valchov (former German name: Walchow) and was named after this place.

Early written references to this resin go back to the first half of the 19th century. The age of the resin is given as 100 million years (lower Upper Cretaceous ). Walchowite is thus much younger than Lebanon amber , to which it, as well as other Cretaceous resins from France and Japan, has certain similarities. The resin is mostly found in the form of rounded tubers, the size of a nut to a fist, in the hanging walls of the lignite depots north of Brno .

The fossil resin is made up as follows: hydrogen 10.66%, carbon 80.24%, oxygen 8.92% and nitrogen 0.18% (based on an analysis by Anton Schrötter von Kristelli from 1843). The same sample had a specific gravity of 1.035. The analyzed resin was hardly soluble in ether and alcohol.

The names Neudorfit and Muchit, under which fossil resins were once described, are now considered synonyms for walchowite. Conversely, not all fossil resins found at Valchov are walchowite. A sample from the Valchov site, examined by infrared spectroscopy , was identified as succinite (Baltic amber) , from which walchowite differs considerably.

The worked and unworked amber found in the Celtic oppidum Staré Hradisko from the La Tène period (late Iron Age ), only 20 km from Valchov, could be amber from this deposit or material imported from the Baltic Sea region.

literature

  • Wilhelm Haidinger: Handbook of determining mineralogy. Vienna 1845.
  • Brigitte and Günter Krumbiegel: Bernstein: Fossil resins from all over the world. Weinstadt 1994, ISBN 3-926129-16-6 .

Individual evidence

  1. ^ W. Fuchs, G. Landsmann: About Walchowit. In: Reports of the German Chemical Society (A and B Series) , Vol. 60 (1), Weinheim 1927. pp. 246–249.
  2. ↑ quoted in: Doelter, Leitmeier: Handbuch der Mineralchemie. Volume IV, Part Three, Berlin 1931. pp. 971f.
  3. ^ N. Vavra: Chemical Characterization of Fossil Resins ("Amber") - A Critical Review of Methodes, Problems and Possibilities: Determination of Mineral Species, Botanical Sources and Geographical Attribution . In: Abh. Geol. B.-A. Volume 49, Vienna 1993.
  4. ^ W. Winkler: FT-Raman spectroscopic investigation of selected local European fossil resins. - In: Properties of amber and other fossil resins from around the world. Vienna 2011, pp. 55–64.
  5. ^ J. Čižmářová: Amber on the Celtic oppidum Stare Hradisko in Moravia. Arheološki vestnik (Arh. Vest.) 47, 1996, pp. 173-182.