Changoite

Changoite
Yellowish crystals of changoite associated to hexagonal colorless caracolite in an aesthetic combination.
General
CategorySulfate mineral
Formula
(repeating unit)		Na2Zn(SO4)2·4H2O
IMA symbolCgo[1]
Strunz classification7.CC.50 (10 ed)
6/C.18-25 (8 ed)
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/a
Unit cella = 11.08, b = 8.25,
c = 5.53 [Å], β = 100.18° (approximated); Z = 2
Identification
ColorColorless
Crystal habitAnhedral crystals, in small veins
Mohs scale hardness2-3
LusterVitreous
StreakWhite
DiaphaneityTransparent
Specific gravity2.50 (measured)
Optical propertiesBiaxal (-)
Refractive indexnα=1.51, nβ=1.51, nγ=1.52 (approximated)
2V angle83° (calculated)
References[2][3][4][5]

Changoite is a rare zinc sulfate mineral with the formula Na2Zn(SO4)2·4H2O.[5][3] Chagoite was discovered in the San Francisco Mine near Sierra Gorda, Antofagasta, Chile.[4] The mineral is a zinc-analogue of blödite, cobaltoblödite, manganoblödite and nickelblödite - other representatives of the blödite group.[5] In terms of chemistry changoite is somewhat similar to gordaite.[6] The mineral's name comes from the early inhabitants of Chile - Changos.[4]

Traces of magnesium and calcium in changoite are negligible.[4]

Minerals associating with changoite are gypsum, zinc-bearing paratacamite, and thénardite.[3]

References

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Mineralienatlas
  3. ^ a b c 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.
  4. ^ a b c d "Chagoite- Handbook of Mineralogy" (PDF). Handbookofmineralogy.org. Retrieved 2016-03-11.
  5. ^ a b c "Changoite: Changoite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  6. ^ "Gordaite: Gordaite mineral information and data". Mindat.org. Retrieved 2016-03-11.

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