Kröhnkite
A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
About Kröhnkite
Formula:
Na2Cu(SO4)2 · 2H2O
Colour:
Blue, greenish-blue; light blue to colourless in transmitted light
Lustre:
Vitreous
Hardness:
2½ - 3
Specific Gravity:
2.90
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Johann Berthold Christian Kröhnke (10 December 1832, Glückstadt, Schleswig-Holstein, Germany - 14 June 1915, Hamburg, Germany), chemist who was working in Chile and first analyzed the mineral. He later became a German consul to Chile.
Unique Identifiers
Mindat ID:
2277
Long-form identifier:
mindat:1:1:2277:0
GUID
(UUID V4):
(UUID V4):
7067ebe1-4c5b-4349-af7f-243fc4894b82
IMA Classification of Kröhnkite
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Kröhnkite
7.CC.30
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
C : With medium-sized and large cations
29.3.2.1
29 : HYDRATED ACID AND NORMAL SULFATES
3 : A2B(XO4)2·xH2O
29 : HYDRATED ACID AND NORMAL SULFATES
3 : A2B(XO4)2·xH2O
25.2.11
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 |
|---|---|---|
| Khk | 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 Kröhnkite
Vitreous
Transparency:
Transparent
Colour:
Blue, greenish-blue; light blue to colourless in transmitted light
Streak:
White
Hardness:
2½ - 3 on Mohs scale
Cleavage:
Perfect
On {010} perfect; on {1¯01} very imperfect.
On {010} perfect; on {1¯01} very imperfect.
Fracture:
Conchoidal
Density:
2.90 g/cm3 (Measured) 2.913 g/cm3 (Calculated)
Optical Data of Kröhnkite
Type:
Biaxial (-)
RI values:
nα = 1.544 nβ = 1.578 nγ = 1.601
2V:
Measured: 78° , Calculated: 76°
Max Birefringence:
δ = 0.057
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
weak
Chemistry of Kröhnkite
Mindat Formula:
Na2Cu(SO4)2 · 2H2O
Crystallography of Kröhnkite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 5.807(1) Å, b = 12.656(2) Å, c = 5.517(1) Å
β = 108.32(1)°
β = 108.32(1)°
Ratio:
a:b:c = 0.459 : 1 : 0.436
Unit Cell V:
384.91 ų (Calculated from Unit Cell)
Morphology:
Crystals short prismatic [001]; also octahedral with large {110} and {011} and rather elongated [100]. Prismatic or fibrous aggregates and crusts; massive, granular.
Twinning:
On {101}, common; twins heart-shaped at times.
Comment:
Cell data from Hawthorne and Ferguson (1975).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.33 Å | (100) |
| 3.278 Å | (90) |
| 2.757 Å | (90) |
| 2.925 Å | (80) |
| 3.715 Å | (60) |
| 4.145 Å | (40) |
| 3.099 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] |
Type Occurrence of Kröhnkite
Associated Minerals at Type Locality:
Synonyms of Kröhnkite
Other Language Names for Kröhnkite
Relationship of Kröhnkite to other Species
Member of:
Other Members of this group:
| Brandtite | Ca2Mn2+(AsO4)2 · 2H2O | Mon. 2/m : P21/b |
| Dobšináite | Ca2Ca(AsO4)2 · 2H2O | Mon. 2/m : P21/b |
| Roselite | Ca2Co(AsO4)2 · 2H2O | Mon. 2/m : P21/b |
| Rruffite | Ca2Cu(AsO4)2 · 2H2O | Mon. 2/m : P21/b |
| Unnamed (Fe2+-analogue of Brandtite) | Ca2Fe2+(AsO4)2 · 2H2O | |
| Wendwilsonite | Ca2Mg(AsO4)2 · 2H2O | Mon. 2/m : P21/b |
| Zincroselite | Ca2Zn(AsO4)2 · 2H2O | Mon. 2/m : P21/b |
Common Associates
Associated Minerals Based on Photo Data:
| 22 photos of Kröhnkite associated with Natrochalcite | NaCu2(SO4)2(OH) · 2H2O |
| 9 photos of Kröhnkite associated with Changoite | Na2Zn(SO4)2 · 4H2O |
| 7 photos of Kröhnkite associated with Caracolite | Na3Pb2(SO4)3Cl |
| 7 photos of Kröhnkite associated with Salesite | Cu(IO3)(OH) |
| 6 photos of Kröhnkite associated with Antlerite | Cu3(SO4)(OH)4 |
| 4 photos of Kröhnkite associated with Atacamite | Cu2(OH)3Cl |
| 3 photos of Kröhnkite associated with Amarantite | Fe3+2(SO4)2O · 7H2O |
| 2 photos of Kröhnkite associated with Brochantite | Cu4(SO4)(OH)6 |
| 2 photos of Kröhnkite associated with Antofagastaite | Na2Ca(SO4)2 · 1.5H2O |
| 2 photos of Kröhnkite associated with Metasideronatrite | Na2Fe(SO4)2(OH) · H2O |
Related Minerals - Strunz-mindat Grouping
| 7.CC. | Cobaltoblödite | Na2Co(SO4)2 · 4H2O |
| 7.CC. | Andychristyite | PbCu2+Te6+O5(H2O) |
| 7.CC. | Ammoniovoltaite | (NH4)2Fe2+5Fe3+3Al(SO4)12(H2O)18 |
| 7.CC.05 | Krausite | KFe(SO4)2 · H2O |
| 7.CC.10 | Tamarugite | NaAl(SO4)2 · 6H2O |
| 7.CC.15 | Kalinite | KAl(SO4)2 · 11H2O |
| 7.CC.15 | Mendozite | NaAl(SO4)2 · 11H2O |
| 7.CC.20 | Lonecreekite | (NH4)Fe3+(SO4)2 · 12H2O |
| 7.CC.20 | Alum-(K) | KAl(SO4)2 · 12H2O |
| 7.CC.20 | Alum-(Na) | NaAl(SO4)2 · 12H2O |
| 7.CC.20 | Tschermigite | (NH4)Al(SO4)2 · 12H2O |
| 7.CC.20 | Lanmuchangite | Tl+Al(SO4)2 · 12H2O |
| 7.CC.25 | Voltaite | K2Fe2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Zincovoltaite | K2Zn5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Pertlikite | K2(Fe2+,Mg)2Mg4Fe3+2Al(SO4)12 · 18H2O |
| 7.CC.25 | Ammoniomagnesiovoltaite | (NH4)2Mg2+5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.25 | Magnesiovoltaite | K2Mg5Fe3+3Al(SO4)12 · 18H2O |
| 7.CC.35 | Ferrinatrite | Na3Fe(SO4)3 · 3H2O |
| 7.CC.40 | Goldichite | KFe(SO4)2 · 4H2O |
| 7.CC.45 | Löweite | Na12Mg7(SO4)13 · 15H2O |
| 7.CC.50 | Blödite | Na2Mg(SO4)2 · 4H2O |
| 7.CC.50 | Nickelblödite | Na2(Ni,Mg)(SO4)2 · 4H2O |
| 7.CC.50 | Changoite | Na2Zn(SO4)2 · 4H2O |
| 7.CC.55 | Leonite | K2Mg(SO4)2 · 4H2O |
| 7.CC.55 | Mereiterite | K2Fe(SO4)2 · 4H2O |
| 7.CC.60 | Boussingaultite | (NH4)2Mg(SO4)2 · 6H2O |
| 7.CC.60 | Cyanochroite | K2Cu(SO4)2 · 6H2O |
| 7.CC.60 | Mohrite | (NH4)2Fe(SO4)2 · 6H2O |
| 7.CC.60 | Nickelboussingaultite | (NH4)2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Picromerite | K2Mg(SO4)2 · 6H2O |
| 7.CC.60 | Nickelpicromerite | K2Ni(SO4)2 · 6H2O |
| 7.CC.60 | Katerinopoulosite | (NH4)2Zn(SO4)2 · 6H2O |
| 7.CC.65 | Polyhalite | K2Ca2Mg(SO4)4 · 2H2O |
| 7.CC.70 | Leightonite | K2Ca2Cu(SO4)4 · 2H2O |
| 7.CC.75 | Amarillite | NaFe(SO4)2 · 6H2O |
| 7.CC.80 | Konyaite | Na2Mg(SO4)2 · 5H2O |
| 7.CC.85 | Wattevilleite | Na2Ca(SO4)2 · 4H2O (?) |
| 7.CC.85 | Xocolatlite | Ca2Mn4+2(Te6+O6)2 · H2O |
| 7.CC.90 | Eckhardite | (Ca,Pb)Cu2+Te6+O5(H2O) |
Other Information
Notes:
Water soluble.
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 Kröhnkite
mindat.org URL:
https://www.mindat.org/min-2277.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Kröhnkite
Reference List:
Palache, C., Warren, C.H. (1908) Kröhnkite, Natrochalcite. American Journal of Science: 26: 342-348.
Kolitsch, Uwe, Fleck, Michel (2006) Third update on compounds with krohnkite-type chains: the crystal structure of wendwilsonite [Ca2Mg(AsO4)22H2O] and the new triclinic structure types of synthetic AgSc(CrO4)22H2O and M2Cu(Cr2O7)22H2O (M = Rb, Cs) European Journal of Mineralogy, 18 (4) 471-482 doi:10.1127/0935-1221/2006/0018-0471
Majzlan, Juraj, Zittlau, Arne H., Grevel, Klaus-Dieter, Schliesser, Jacob, Woodfield, Brian F., Dachs, Edgar, Števko, Martin, Chovan, Martin, Plášil, Jakub, Sejkora, Jiří, Milovská, Stanislava (2015) Thermodynamic Properties and Phase Equilibria of the Secondary Copper Minerals Libethenite, Olivenite, Pseudomalachite, Kröhnkite, Cyanochroite, and Devilline. The Canadian Mineralogist, 53 (5) 937-960 doi:10.3749/canmin.1400066
Localities for Kröhnkite
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.
Argentina | |
| Sureda (1978) |
Australia | |
| Birch et al. (1997) |
| Harris et al. (2003) |
| Simpson Mineral Collection of the ... +1 other reference |
Austria | |
| 50. +1 other reference |
Chile | |
| e-rocks.com (2022) |
| SEM-EDS by Igor V. Pekov |
| samples analysed by Dr. Tony Kampf | |
| www.ontariominerals.com |
| M.Dini & A.Molina collection | |
| Samples analysed by Dr. Jochen Schlüter (Hamburg University) +1 other reference | |
| Palache et al. (1908) +4 other references |
| Palache et al. (1951) |
| British Natural History Museum online ... | |
| Palache et al. (1951) | |
| CD with abstracts +1 other reference |
| Saric (1978) |
| Sulphides analysed by geology dep. of ... +1 other reference |
China | |
| Yingxia Xu et al. (2008) |
Greece | |
| Rieck et al. (2018) |
| |
| Branko Rieck collection | |
Hungary | |
| |
| Koch: Minerals of Hungary |
Iceland | |
| Balić-Žunić et al. (2016) |
Italy | |
| Balassone et al. (2019) |
| Quagliarella (1966) |
Poland | |
| Łukasz Kruszewski PXRD & EPMA data (2019) |
| Cu +2 other references |
Romania | |
| Onac +4 other references |
Spain | |
| Calvo Rebollar et al. (2022) |
UK | |
| Golley et al. (1995) |
USA | |
| Luetcke (n.d.) |
| Van Nostrand Reinholt Press: 298. +3 other references |
| [Mineralogical Record 20 129-142] | |
| Plášil et al. (2013) |
| Dietrich (1990) |
Quick NavTopAbout KröhnkiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
La Compañia Mine, Sierra Gorda, Antofagasta Province, Antofagasta, Chile