Garnierite

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Garnierite

Garnierite is a collective term for a green nickel ore that occurs in pockets and crevices within weathered ultramafic rocks (especially serpentinite ). It is formed during the lateritic weathering of ultramafic rocks and occurs in numerous lateritic nickel deposits around the world.

Garnierite was named in 1875 by Edward Daniel Clarke after the French geologist Jules Garnier , who first discovered this ore in New Caledonia in 1864 . Since it occurs in large quantities near the capital Nouméa , it was also referred to synonymously as Nouméait (after Liversidge , 1874).

composition

Garnierite consists of one or more minerals of the phyllosilicates serpentine , talc , smectite , chlorite and sepiolite in which a considerable proportion of the magnesium has been replaced by nickel . There are special names for the nickel-rich varieties of these minerals. A detailed examination of the garnierite ores from the Falcondo mine in the Dominican Republic revealed a composition of three mineral groups: Talc - Willemseit (up to 25% by weight Ni); Lizardite (serpentine) - Népouite (up to 34% by weight Ni); Sepiolite - Falcondoite (up to 24% by weight Ni).

Emergence

The lateritization of ultramafic rocks causes a strong solution of magnesium and silicon , which leads to a strong accumulation of residues of iron and nickel in a goethite- rich surface layer (nickel- limonite ore ). A part of the nickel is shifted downwards in dissolved form and bound in the underlying weathered ultramafic rock (serpentinite decomposition). This process leads to a general, relatively small increase in nickel throughout the decomposed rock (nickel silicate ore, nickel saprolite ) and, moreover, to a precipitation of Ni-rich garnierite in pockets and crevices of the decomposed rock. Garnierite ore is of little economic importance nowadays.

See also

Web links

Commons : Garnierit  - collection of images, videos and audio files
Wiktionary: Garnierit  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Hans Lüschen: The names of the stones. The mineral kingdom in the mirror of language . 2nd Edition. Ott Verlag, Thun 1979, ISBN 3-7225-6265-1 , p. 222 .
  2. ^ GW Brindley, PT Hang: The nature of garnierite. Structures, chemical composition and color characteristics , Clays and Clay Mineral. 21, 1973, pp. 27-40.
  3. JA Proenza et al .: Garnierite mineralization from Falcondo Ni-laterite deposit (Dominican Republic) (PDF; 250 kB) Revista de la Sociedad Espanola de Mineralogia. Macla no.9 September 2008, p. 197.
  4. JA Proenza et al .: Garnierite mineralization from Falcondo Ni-laterite deposit (Dominican Republic) (PDF; 250 kB) Revista de la Sociedad Espanola de Mineralogia. Macla no.9 September 2008, p. 198.
  5. W. Schellmann: An introduction in laterite. Economic relevance: Nickel laterites . laterite.de