Delessit

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Pseudomorphism from quartz to laumontite , covered with a crust of delessite

Delessit is considered either as a magnesium-rich variety of mineral chamosite or as an iron-rich variety of the mineral clinochlor from the group of chlorites . It consists of a water-containing double silicate of magnesium oxide , iron (II) oxide , clay and iron (III) oxide . Its mixed formula is given as (Mg, Fe, Fe, Al) (Si, Al) 4 O 10 (O, OH) 8 .

Delessit was first described in 1850 by Carl Friedrich Naumann , who named the variety after the mineralogist and geologist Achille-Joseph Delesse .

Delessit is found microcrystalline in scaly and short-fiber aggregates , which in the so-called melaphyres or almond stone melaphyres of the Rotliegend form only the olive to blackish-green crusts of other almonds and drusen .

literature

  • H. Rosenbusch: Microscopic physiography of minerals and rocks. A help book for microscopic rock studies . 4th, revised edition. Volume II, 2nd half. Schweizerbartsche Verlagsbuchhandlung, Stuttgart 1909 ( available online at archive.org  - Internet Archive ).
  • Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 592 .

Web links

Individual evidence

  1. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  758 (first edition: 1891).
  2. ^ Helmut Schrätze , Karl-Ludwig Weiner : Mineralogie. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp.  835 .
  3. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  4. ↑ a b c Mindat - Delessite (English)