Yellow earth

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Gelberde (Greek μήλινος melinos for (apple) yellow-green), also known by the synonym melinite , is the name for a mixture of substances, more precisely yellow-colored soils of different origins due to iron oxide compounds due to lack of humus .

Occurrence and use

Yellow earth is mostly found in the form of coarse, thick schisty masses with earthy breakage and ocher yellow color. In addition to iron oxides and alumina, further chemical components are silica , magnesia and water. Depending on the source, yellow earth is also viewed as a mixture of the brown iron ore limonite and clay .

Gelberde was found near Wehrau in the Prussian Lausitz (today Osiecznica in Poland), near Amberg in Bavaria and near Schoningen am Solling in Lower Saxony. It was mainly used as a yellow paint.

properties

Yellow earth feels greasy and turns into powder in the water. It rubs off, which means you can also write with it. The Mohs hardness is about 1 to 2 and the density about 2.24 g / cm³.

Yellow earth is infusible in front of the soldering tube, but the color changes to reddish when heated. It is partially soluble in hydrochloric acid. Gelberde as a mixture of minerals from German sites was examined in the 1860s. Different colors of yellow, brown or gray became known.

literature

  • Geological Federal Institute (Austria), KK Geologische Reichsanstalt (Austria), Reich Office for Soil Research (Germany) Branch Vienna: Yearbook - Geological Federal Institute , Volume 4, The Branch, 1853
  • Gustav Leonhard: Fundamentals of the mineralogy edition . 2nd, revised edition. CF Winter'sche Verlagshandlung, Leipzig, Heidelberg 1860, p. 297 ( available online at archive.org  - Internet Archive ).
  • Otto Wishes: The mineral kingdom . 1st edition. Salzwasser Verlag, Paderborn 2011, ISBN 978-3-86444-110-3 , p. 238 ( limited preview in Google Book Search - reprint of the original from 1885).
  • Yellow earth . In: Meyers Konversations-Lexikon . 4th edition. Volume 7, Verlag des Bibliographisches Institut, Leipzig / Vienna 1885–1892, p. 44.

Individual evidence

  1. ^ Henry George Liddell, Robert Scott: A Greek-English Lexicon
  2. ↑ Melinit . In: Meyers Konversations-Lexikon . 4th edition. Volume 11, Verlag des Bibliographisches Institut, Leipzig / Vienna 1885–1892, p. 450.
  3. ↑ Rudolf Graubner: Lexicon of Geology, Minerals and Rocks . Emil Vollmer Verlag, Munich 1980, ISBN 3-87876-327-1 , p. 129 .
  4. ↑ a b c Otto Wünsche: The mineral kingdom . 1st edition. Salzwasser Verlag, Paderborn 2011, ISBN 978-3-86444-110-3 , p. 238 ( limited preview in Google Book Search - reprint of the original from 1885).
  5. ^ Margret Hamilton: The notebooks of the mineralogist and petrographer Friedrich Becke 1855-1931 . Vandenhoeck & Ruprecht, Göttingen 2017, ISBN 978-3-8470-0640-4 , p. 291 ( limited preview in Google Book search).
  6. ↑ Yearbook - Geologische Bundesanstalt , (Chemical Analysis) pages 828, 829