Népouite

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Népouite
Specific gravity
3.18 to 3.24 (measured)
Optical propertiesbiaxial (−)
Refractive indexnα = 1.600 – 1.630 nγ = 1.635 – 1.650
Birefringence0.035
Pleochroismweak. X = green to yellow green Z = yellow-green
References[2][3][4]

Népouite is a rare nickel

Lizard Complex in Cornwall, England) in which all of the nickel is replaced by magnesium, formula Mg3(Si2O5)(OH)4.[6] These two minerals form a series; intermediate compositions are possible, with varying proportions of nickel to magnesium.[7]

Pecoraite is another rare mineral with the same chemical formula as népouite, but a different structure; such minerals are said to be dimorphs of each other, in the same way as graphite is a dimorph of diamond. Népouite, lizardite and pecoraite are all members of the kaolinite-serpentine group.[8]

phyllosilicates (sheet silicates), including népouite. Associated minerals include calcite, chlorite, goethite, halloysite, nontronite, pimelite, quartz, sepiolite, serpentine, talc and willemseite
.

As well as the type locality in New Caledonia, it has been found in Australia, Austria, the Czech Republic, the Democratic Republic of Congo, Germany, Greece, Italy, Japan, Morocco,[9] Poland, Russia, South Africa and the United States.

Structure

Space group Ccm21. Unit cell: a = 5.31

Å
, b = 9.19 Å, c = 14.50 Å

X-ray powder diffraction data
d spacing 7.31 4.55 3.63 2.89 2.50 2.31 2.20 1.53
relative intensity 10 5 9 6 7 4 4 6

See also

  • Lizardite – Magnesium phyllosilicate mineral of the serpentine group (Mg3(Si2O5)(OH)4)
  • Pecoraite – Nickel phyllosilicate mineral of the serpentine group (Ni3(Si2O5)(OH)4)

References

  1. S2CID 235729616
    .
  2. ^ http://rruff.geo.arizona.edu/doclib/hom/nepouite.pdf Handbook of Mineralogy
  3. ^ http://www.mindat.org/min-2882.html Mindat.org
  4. ^ http://www.webmineral.com/data/Nepouite.shtml Webmineral data
  5. ^ M. E. Glaser (1907). "Note sur une espèce minérale nouvelle, la népouite, silicate hydraté de nickel et de magnésie. Bulletin de Minéralogie. Année 1907, 30 (1), pp. 17–28. – Sur le site de Persée" [Note on a new mineral species, népouite, hydrated silicate of nickel and magnesia. Bulletin de Minéralogie. Year 1907, 30 (1), pp. 17–28. – On the Persée website]. persee.fr (in French). Retrieved 28 November 2022.
  6. ^ "Lizardite-Népouite Series".
  7. ^ American Mineralogist (1975): 60: 863–871
  8. ^ Dana’s New Mineralogy, Eighth Edition, 1997, Gaines et al., Wiley.
  9. ^ Mineralogical Record 38-5, page 384
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