Changoite

Changoite
General
Category Sulfate mineral
Formula
(repeating unit)		 Na2Zn(SO4)2•4H2O
Strunz classification 6/C.18-25
Crystal system Monoclinic, P21/a
Unit cell a=11.08, b=8.25, c=5.53 [Å], β=100.18o (approximated)
Identification
Color Colorless
Crystal habit anhedral crystals, in small veins
Crystal symmetry Monoclinic - Prismatic (2/m)
Mohs scale hardness 2-3
Luster Vitreous
Streak White
Diaphaneity Trasnparent
Density 2.50 (measured)
Optical properties Biaxal (-)
Refractive index nα=1.51, nβ=1.51, nγ=1.52 (approximated)
2V angle 83o (calculated)
References [1][2][3]

Changoite is a rare nickel mineral with the formula Na2Zn(SO4)2•4H2O.[3][1] Chagoite was discovered in San Francisco mine near Sierra Gorda, Antofagasta, Chile.[2] The mineral is a zinc-analogue of blödite, cobaltoblödite, manganoblödite and nickelblödite - other representatives of the blödite group.[3] In terms of chemistry changoite is somewhat similar to gordaite.[4] Mineral's name comes from the early inhabitants of Chile - Changos.[2]

Notes on chemistry

Traces of magnesium and calcium in changoite are negligible.[2]

Association and origin

Minerals associating with changoite are gypsum, zinc-bearing paratacamite, and thénardite.[1]

References

  1. 1 2 3 Schlüter, J., Klaska, K.-H., and Gebhard, G., 1999. Changoite, Na2Zn(SO4)2·4H2O, the zinc analogue of blödite, a new mineral from Sierra Gorda, Antofagasta, Chile. Neues Jahrbuch für Mineralogie - Monatshefte 3(3), 97-103.
  2. 1 2 3 4 "Chagoite- Handbook of Mineralogy" (PDF). Handbookofmineralogy.org. Retrieved 2016-03-11.
  3. 1 2 3 "Changoite: Changoite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  4. ↑ "Gordaite: Gordaite mineral information and data". Mindat.org. Retrieved 2016-03-11.
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