Natrochalcite
A valid IMA mineral species - grandfathered
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About Natrochalcite
Formula:
NaCu2(SO4)2(OH) · 2H2O
Colour:
Bright green; green in transmitted light.
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
3.47 - 3.51
Crystal System:
Monoclinic
Member of:
Name:
In allusion to the composition, containing sodium (Latin = NATRium) and copper (CHALCo-)
Unique Identifiers
Mindat ID:
2853
Long-form identifier:
mindat:1:1:2853:6
IMA Classification of Natrochalcite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
NaCu2+2(S6+O4)2(OH)·H2O
First published:
1908
Classification of Natrochalcite
7.DF.15
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
31.8.1.1
31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
8 : (AB)3(XO4)2Zq·xH2O
31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
8 : (AB)3(XO4)2Zq·xH2O
25.2.12
25 : Sulphates
2 : Sulphates of Cu and Ag
25 : Sulphates
2 : Sulphates of Cu and Ag
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Nch | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Natrochalcite
Vitreous
Transparency:
Transparent
Colour:
Bright green; green in transmitted light.
Streak:
Greenish white
Hardness:
4½ on Mohs scale
Cleavage:
Perfect
On {001}, perfect.
On {001}, perfect.
Density:
3.47 - 3.51 g/cm3 (Measured) 3.54 g/cm3 (Calculated)
Optical Data of Natrochalcite
Type:
Biaxial (+)
RI values:
nα = 1.649 nβ = 1.655 nγ = 1.714
2V:
Measured: 36° , Calculated: 38°
Max. Birefringence:
δ = 0.065
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r < v strong
Chemistry of Natrochalcite
Mindat Formula:
NaCu2(SO4)2(OH) · 2H2O
Element Weights:
Crystallography of Natrochalcite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 8.809(1) Å, b = 6.187(1) Å, c = 7.509(1) Å
β = 118.74(1)°
β = 118.74(1)°
Ratio:
a:b:c = 1.424 : 1 : 1.214
Unit Cell V:
358.83 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals pyramidal {111}. {110} commonly well-developed, but faces of the remaining forms are usually small and often not present in their full complement; cross-fiber veinlets.
Twinning:
Contact and interpenetrating.
Comment:
Synthetic
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0011040 | Natrochalcite | Chevrier G, Giester G, Zemann J (1993) Neutron refinements of NaCu2(H3O2)(SO4)2 and RbCu2(H3O2)(SeO4)2: Variation of the hydrogen bond system in the natrochalcite-type series Zeitschrift fur Kristallographie 206 7-14 |  | 1993 | synthetic | 0 | 293 |
| 0010968 | Natrochalcite | Giester G, Zemann J (1987) The crystal structure of the natrochalcite-type compounds Me+Cu2(OH)(zO4)2*H2O [Me+ = Na,K,Rb; z = S,Se], with special reference to the hydrogen bonds Zeitschrift fur Kristallographie 179 431-442 | | 1987 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.797 Å | (100) |
| 6.57 Å | (80) |
| 3.44 Å | (80) |
| 2.522 Å | (80) |
| 3.20 Å | (70) |
| 4.82 Å | (60) |
| 2.302 Å | (60) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] |
Type Occurrence of Natrochalcite
General Appearance of Type Material:
Clusters of crystals and twin groups to 1.5 cm. Single crystals and fibrous or acicular aggregates to 4 cm. Solid crusts to 2 cm thick.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 97537, 97538.
Geological Setting of Type Material:
Oxidation zone of a copper deposit in an arid environment.
Associated Minerals at Type Locality:
Other Language Names for Natrochalcite
Relationship of Natrochalcite to other Species
Member of:
Other Members of Tsumcorite Group:
| Alumolukrahnite | Ca[CuAl](AsO4)2(H2O,OH)2 | Tric. 1 : P1 |
| Cabalzarite | CaMg2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Cobaltlotharmeyerite | CaCo2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Cobalttsumcorite | PbCo2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Ferrilotharmeyerite | CaZnFe3+(AsO4)2(OH) · H2O | Mon. 2/m : B2/m |
| Gartrellite | PbCuFe3+(AsO4)2(OH) · H2O | Tric. 1 : P1 |
| Helmutwinklerite | PbZn2(AsO4)2 · 2H2O | Tric. 1 : P1 |
| Kaliochalcite | KCu2(SO4)2[(OH)(H2O)] | Mon. 2/m : B2/m |
| Krettnichite | PbMn3+2(VO4)2(OH)2 | Mon. 2/m : B2/m |
| Lotharmeyerite | CaZn2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Lukrahnite | CaCuFe3+(AsO4)2(OH,H2O)2 | Tric. 1 : P1 |
| Manganlotharmeyerite | CaMn3+2(AsO4)2(OH)2 | Mon. 2/m : B2/m |
| Mawbyite | PbFe3+2(AsO4)2(OH)2 | Mon. 2/m : B2/m |
| Mounanaite | PbFe3+2(VO4)2(OH)2 | Mon. 2/m : B2/m |
| Nickellotharmeyerite | CaNi2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Nickelschneebergite | BiNi2(AsO4)2(OH) · H2O | Mon. 2/m : B2/m |
| Nickeltsumcorite | Pb(Ni,Fe3+)2(AsO4)2(H2O,OH)2 | Mon. 2/m : B2/m |
| Phosphogartrellite | PbCuFe3+(PO4)2(OH,H2O)2 | Tric. 1 : P1 |
| Rappoldite | PbCo2(AsO4)2 · 2H2O | Tric. 1 : P1 |
| Schneebergite | BiCo2(AsO4)2(OH) · H2O | Mon. 2/m : B2/m |
| Thometzekite | PbCu2+2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Tsumcorite | PbZn2(AsO4)2 · 2H2O | Mon. 2/m : B2/m |
| Yancowinnaite | PbCuAl(AsO4)2OH · H2O | Tric. 1 : P1 |
| Zincgartrellite | PbZn2(AsO4)2(H2O,OH)2 | Tric. 1 : P1 |
Common Associates
Associations Based on Photo Data:
| 22 photos of Natrochalcite associated with Kröhnkite | Na2Cu(SO4)2 · 2H2O |
| 9 photos of Natrochalcite associated with Leightonite | K2Ca2Cu(SO4)4 · 2H2O |
| 1 photo of Natrochalcite associated with Paratacamite | Cu3(Cu,Zn)(OH)6Cl2 |
| 1 photo of Natrochalcite associated with Lammerite | Cu3(AsO4)2 |
| 1 photo of Natrochalcite associated with Antlerite | Cu3(SO4)(OH)4 |
| 1 photo of Natrochalcite associated with Native Copper | Cu |
| 1 photo of Natrochalcite associated with Dioptase | CuSiO3 · H2O |
Related Minerals - Strunz-mindat Grouping
| 7.DF. | Siligiite | [Pb(H2O)5(SO4)][Zn9(OH)18] |
| 7.DF. | Alcaparrosaite | K3Ti4+Fe3+(SO4)4O(H2O)2 |
| 7.DF. | Flaggite | Pb4Cu2+4Te6+2(SO4)2O11(OH)2(H2O) |
| 7.DF. | Bairdite | Pb2Cu2+4Te6+2O10(OH)2(SO4) · H2O |
| 7.DF. | Tzeferisite | CaZn8(SO4)2(OH)12Cl2(H2O)9 |
| 7.DF. | Cherokeeite | [Pb2Zn(OH)4](SO4) · H2O |
| 7.DF. | Ammoniomathesiusite | (NH4)5(UO2)4(SO4)4(VO5) · 4H2O |
| 7.DF. | Sigogglinite | [Pb6Zn(OH)8]2(SO4)6 · (H2O)8-x |
| 7.DF.X | Blueridgeite | [Pb8Zn3Cu2+(OH)16](SO4)2(S2O3)2 · 2H2O |
| 7.DF. | Erssonite | Mg7Fe3+2(OH)18[Ca(H2O)6](SO4)2 · 12H2O |
| 7.DF. | Poellmannite | Ca6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2O |
| 7.DF. | Carlsonite | (NH4)5Fe3+3O(SO4)6 · 7H2O |
| 7.DF. | Cuprocherokeeite | [Pb8Zn3Cu2+(OH)16](SO4)4 · 4H2O |
| 7.DF. | Haywoodite | [Pb(H2O)10][Zn12(OH)20(H2O)(SO4)3] |
| 7.DF. | Chromschieffelinite | Pb10Te6+6O20(OH)14(CrO4)(H2O)5 |
| 7.DF.05 | Uklonskovite | NaMg(SO4)F · 2H2O |
| 7.DF.10 | Kainite | KMg(SO4)Cl · 3H2O |
| 7.DF.10 | Kaliochalcite | KCu2(SO4)2[(OH)(H2O)] |
| 7.DF.17 | Genplesite | Ca3Sn(SO4)2(OH)6 · 3H2O |
| 7.DF.17 | 'Unnamed (Ba-Sb Silicate-Sulphate-Hydroxide-Hydrate)' | Ba3Sb5+[(Si,S)O3(OH)]2(OH,O)6 · 3H2O |
| 7.DF.20 | Sideronatrite | Na2Fe(SO4)2(OH) · 3H2O |
| 7.DF.20 | Metasideronatrite | Na2Fe(SO4)2(OH) · H2O |
| 7.DF.25 | Fleischerite | Pb3Ge(SO4)2(OH)6 · 3H2O |
| 7.DF.25 | Mallestigite | Pb3Sb5+(SO4)(AsO4)(OH)6 · 3H2O |
| 7.DF.25 | Schaurteite | Ca3Ge(SO4)2(OH)6 · 4H2O |
| 7.DF.25 | Despujolsite | Ca3Mn4+(SO4)2(OH)6 · 3H2O |
| 7.DF.30 | Slavíkite | (H3O+)3Mg6Fe15(SO4)21(OH)18 · 98H2O |
| 7.DF.35 | Metavoltine | K2Na6Fe2+Fe3+6O2(SO4)12 · 18H2O |
| 7.DF.40 | Lannonite | Mg2Ca4Al4(SO4)8F8 · 24H2O |
| 7.DF.40 | Vlodavetsite | AlCa2(SO4)2F2Cl · 4H2O |
| 7.DF.45 | Peretaite | Ca(SbO)4(SO4)2(OH)2 · 2H2O |
| 7.DF.50 | Gordaite | NaZn4(SO4)(OH)6Cl · 6H2O |
| 7.DF.50 | Calamaite | Na2TiO(SO4)2 · 2H2O |
| 7.DF.52 | Huizingite-(Al) | [(NH4)9(SO4)2][(Al,Fe3+)3(OH)2(H2O)4(SO4)6] |
| 7.DF.52 | Scordariite | K8(Fe3+0.67◻0.33)[Fe3+3O(SO4)6]2 · 14H2O |
| 7.DF.55 | Clairite | (NH4)2Fe3(SO4)4(OH)3 · 3H2O |
| 7.DF.55 | Giacovazzoite | K5Fe3+3O(SO4)6 · 10H2O |
| 7.DF.57 | Magnanelliite | K3Fe3+2(SO4)4(OH)(H2O)2 |
| 7.DF.60 | Arzrunite | Cu4Pb2(SO4)(OH)4Cl6 · 2H2O (?) |
| 7.DF.60 | Evdokimovite | Tl4(VO)3(SO4)5(H2O)5 |
| 7.DF.62 | Bridgesite-(Ce) | CaCe2Cu6(SO4)4(OH)12 · 8H2O |
| 7.DF.65 | Elyite | Pb4Cu(SO4)O2(OH)4 · H2O |
| 7.DF.70 | Yecoraite | Fe3+3Bi5(Te6+O4)2(Te4+O3)O9 · 9H2O |
| 7.DF.70 | Lautenthalite | PbCu4(SO4)2(OH)6 · 3H2O |
| 7.DF.75 | Riomarinaite | Bi(SO4)(OH) · H2O |
| 7.DF.80 | Dukeite | Bi3+24Cr6+8O57(OH)6 · 3H2O |
Other Information
Notes:
Slowly soluble in water. Readily soluble in acids.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Natrochalcite
mindat.org URL:
https://www.mindat.org/min-2853.html
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References for Natrochalcite
Reference List:
Palache, C., Warren, C.H. (1908) Kröhnkite, natrochalcite (a new mineral), and other sulphates from Chile. American Journal Of Science, S. 4 Vol. 26. 342-348
Palache, Ch.; Warren, C. H. (1908) Kröhnkit, Natrochalcit (ein neues Mineral) und andere Sulfate aus Chile. Zeitschrift für Kristallographie, 45 (1-6). 529-538 doi:10.1524/zkri.1908.45.1.529p.534
Palache, C., Warren, C.H. (1908) Kröhnkite, natrochalcite (a new mineral), and other sulphates from Chile. American Journal Of Science, S. 4 Vol. 26. 342-348
Palache, C. (1939) Kroehnkite and natrochalcite from Chile. American Journal of Science, 237 (7) 447-455 doi:10.2475/ajs.237.7.447
Giester, G., Zemann, J. (1987) The crystal structure of the natrochalcite-type compounds Me+Cu2(OH)(zO4)2·H2O [Me+ = Na, K, Rb; z = S, Se], with special reference to the hydrogen bonds. Zeitschrift für Kristallographie, 179 (1-4). 431-442 doi:10.1524/zkri.1987.179.1-4.431
Giester, G. (1989) The crystal structures of Ag+Cu2(OH)(SO4)2·H2O and Me+Cu2(OH)(SeO4)2·H2O [Me+ = Ag, Tl, NH4], four new representatives of the natrochalcite type, with a note on natural natrochalcite. Zeitschrift für Kristallographie, 187 (3-4). 239-247 doi:10.1524/zkri.1989.187.3-4.239
Chevrier, G., Giester, G., Zemann, J. (1993) Neutron refinements of NaCu2(H3O2)(SO4)2 and RbCu2(H3O2)(SeO4)2: Variation of the hydrogen bond system in the natrochalcite-type series. Zeitschrift für Kristallographie, 206 (1). 7-14 doi:10.1524/zkri.1993.206.part-1.7
Beran, A., Giester, G., Libowitzky, E. (1997) The hydrogen bond system in natrochalcite-type compounds - an FTIR spectroscopic study of the H3O2 unit. Mineralogy and Petrology, 61 (1). 223-235 doi:10.1007/bf01172486
Frost, Ray L., Kloprogge, J. Theo, Martens, Wayde N. (2004) Raman spectroscopy of the arsenates and sulphates of the tsumcorite mineral group. Journal of Raman Spectroscopy, 35 (1). 28-35 doi:10.1002/jrs.1076
Localities for Natrochalcite
Showing 9 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Chile | |
| Anthony et al. (2003) |
| Kampf et al. (2012) |
| Palache et al. (1908) +3 other references |
France | |
| Favreau et al. (2024) |
| Georges FAVREAU collection and EDX ... +1 other reference | |
Greece | |
| Rieck et al. (2018) +1 other reference |
Italy | |
| Balassone et al. (2019) |
| Quagliarella (1966) |
USA | |
| EDS by Tony Kampf |
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Chuquicamata Mine, Chuquicamata District, Calama, El Loa Province, Antofagasta, Chile