Euchroite
A valid IMA mineral species - grandfathered
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About Euchroite
Formula:
Cu2(AsO4)(OH) · 3H2O
Colour:
Bright emerald-green, leek-green; bright bluish green in transmitted light.
Lustre:
Vitreous
Hardness:
3½ - 4
Specific Gravity:
3.44
Crystal System:
Orthorhombic
Name:
Named in 1823 by August Breithaupt from the Greek ευχροια for "beautiful color."
A rare secondary copper arsenate.
Metastable by comparison to related copper arsenates; may be pseudomorphed by olivenite.
In the crystal structure there are two symmetrically-independent Cu sites; the CuO6 octahedra are (typically) strongly distorted (Jahn-Teller distortion). As occurs in a single symmetrically independent site. The Cu-bearing octahedra share edges to form chains || [001]. The arsenate tetrahedra link the chains to constitute a framework, stabilized by hydrogen bonds involving OH groups and water molecules. The hydrogen bonding scheme is complex: there are strong two-center ones and bifurcated three-center ones. There are both bent and almost planar Cu-H2O configurations.
Metastable by comparison to related copper arsenates; may be pseudomorphed by olivenite.
In the crystal structure there are two symmetrically-independent Cu sites; the CuO6 octahedra are (typically) strongly distorted (Jahn-Teller distortion). As occurs in a single symmetrically independent site. The Cu-bearing octahedra share edges to form chains || [001]. The arsenate tetrahedra link the chains to constitute a framework, stabilized by hydrogen bonds involving OH groups and water molecules. The hydrogen bonding scheme is complex: there are strong two-center ones and bifurcated three-center ones. There are both bent and almost planar Cu-H2O configurations.
Unique Identifiers
Mindat ID:
1417
Long-form identifier:
mindat:1:1:1417:1
Similar Names
| Iochroite | A synonym of Tourmaline |
IMA Classification of Euchroite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Cu2+2As5+O4(OH)·3H2O
Classification of Euchroite
8.DC.07
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
C : With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
C : With only medium-sized cations, (OH, etc.):RO4 = 1:1 and < 2:1
42.6.3.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
20.1.8
20 : Arsenates (also arsenates with phosphate, but without other anions)
1 : Arsenates of Cu
20 : Arsenates (also arsenates with phosphate, but without other anions)
1 : Arsenates of Cu
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 |
|---|---|---|
| Euc | 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 Euchroite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Bright emerald-green, leek-green; bright bluish green in transmitted light.
Hardness:
3½ - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Poor/Indistinct
On {101} and {110}, in traces.
On {101} and {110}, in traces.
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
3.44 g/cm3 (Measured) 3.45 g/cm3 (Calculated)
Optical Data of Euchroite
Type:
Biaxial (+)
RI values:
nα = 1.695 nβ = 1.698 nγ = 1.733
2V:
Measured: 28° to 30°, Calculated: 34°
Max. Birefringence:
δ = 0.038
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:
relatively weak
Pleochroism:
Weak
Chemistry of Euchroite
Mindat Formula:
Cu2(AsO4)(OH) · 3H2O
Element Weights:
Elements listed:
Crystallography of Euchroite
Crystal System:
Orthorhombic
Class (H-M):
222 - Disphenoidal
Space Group:
P212121
Cell Parameters:
a = 10.035-10.07 Å, b = 10.4-10.52 Å, c = 6.11-6.12 Å
Ratio:
a:b:c = 0.965 : 1 : 0.588
Unit Cell V:
637.66 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals short prismatic [010] to equant; also thick tabular {100}, rare. Faces m s l striated [010]. Crystals normally holohedral in appearance.
Comment:
V=642.27 (material from Krivovichev et al., 2016)
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 0018354 | Euchroite | Eby R K, Hawthorne F C (1989) Euchroite, a heteropolyhedral framework structure Acta Crystallographica C45 1479-1482 |  | 1989 | Coller cliff, Montana, USA | 0 | 293 |
| 0009302 | Euchroite | Finney J J (1966) Refinement of the crystal structure of euchroite, Cu2(AsO4)(OH)*3H2O Acta Crystallographica 21 437-440 | | 1966 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.34 Å | (100) |
| 2.83 Å | (90) |
| 7.37 Å | (80) |
| 2.64 Å | (80) |
| 2.55 Å | (70) |
| 3.71 Å | (60) |
| 1.510 Å | (50) |
Comments:
Ľubietová, Slovakia. Data from Berry (1951).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Euchroite
General Appearance of Type Material:
Crystals lining crevices in mica schist.
Associated Minerals at Type Locality:
Other Language Names for Euchroite
Common Associates
Associations Based on Photo Data:
| 25 photos of Euchroite associated with Azurite | Cu3(CO3)2(OH)2 |
| 12 photos of Euchroite associated with Olivenite | Cu2(AsO4)(OH) |
| 8 photos of Euchroite associated with Cornubite | Cu5(AsO4)2(OH)4 |
| 7 photos of Euchroite associated with Parnauite | Cu9(AsO4)2(SO4)(OH)10 · 7H2O |
| 7 photos of Euchroite associated with Malachite | Cu2(CO3)(OH)2 |
| 5 photos of Euchroite associated with Langite | Cu4(SO4)(OH)6 · 2H2O |
| 4 photos of Euchroite associated with 'Limonite' | |
| 4 photos of Euchroite associated with Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| 3 photos of Euchroite associated with Pseudomalachite | Cu5(PO4)2(OH)4 |
| 3 photos of Euchroite associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 8.DC. | Ferroberaunite | Fe2+Fe3+5(PO4)4(OH)5 · 6H2O |
| 8.DC. | Césarferreiraite | Fe2+ Fe3+2(AsO4)2(OH)2 · 8H2O |
| 8.DC. | Ferrivauxite | Fe3+Al2(PO4)2(OH)3 · 5H2O |
| 8.DC. | Ianbruceite | Zn2(AsO4)(OH) · 3H2O |
| 8.DC.05 | Nissonite | Cu2Mg2(PO4)2(OH)2 · 5H2O |
| 8.DC.10 | Legrandite | Zn2(AsO4)(OH) · H2O |
| 8.DC.12 | Strashimirite | Cu8(AsO4)4(OH)4 · 5H2O |
| 8.DC.15 | Earlshannonite | Mn2+Fe3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.15 | Kunatite | CuFe3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.15 | 'UM2006-27-PO:FeHZn' | ZnFe3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.15 | 'UKI-2006-(PO:AlCuFeH)' | Fe2+Al3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.15 | Cobaltarthurite | CoFe3+2(AsO4)2(OH)2 · 4H2O |
| 8.DC.15 | Arthurite | CuFe3+2(AsO4)2(OH)2 · 4H2O |
| 8.DC.15 | Ojuelaite | ZnFe3+2(AsO4)2(OH)2 · 4H2O |
| 8.DC.15 | Whitmoreite | Fe2+Fe3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.15 | Bendadaite | Fe2+Fe3+2(AsO4)2(OH)2 · 4H2O |
| 8.DC.17 | Kleemanite | ZnAl2(PO4)2(OH)2 · 3H2O |
| 8.DC.20 | Magnesiobermanite | MgMn3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.20 | Bermanite | Mn2+Mn3+2(PO4)2(OH)2 · 4H2O |
| 8.DC.20 | Coralloite | Mn2+Mn3+2(AsO4)2(OH)2 · 4H2O |
| 8.DC.22 | Kovdorskite | Mg2(PO4)(OH) · 3H2O |
| 8.DC.25 | Zincostrunzite | ZnFe3+2(PO4)2(OH)2 · 6.5H2O |
| 8.DC.25 | Metavauxite | Fe2+Al2(PO4)2(OH)2 · 8H2O |
| 8.DC.25 | Metavivianite | Fe2+Fe3+2(PO4)2(OH)2 · 6H2O |
| 8.DC.25 | Ferristrunzite | Fe3+Fe3+2(PO4)2(OH)3 · 5H2O |
| 8.DC.25 | Strunzite | Mn2+Fe3+2(PO4)2(OH)2 · 6H2O |
| 8.DC.25 | Ferrostrunzite | Fe2+Fe3+2(PO4)2(OH)2 · 6H2O |
| 8.DC.27 | Beraunite | Fe3+6(PO4)4O(OH)4 · 6H2O |
| 8.DC.27 | Tvrdýite | Fe2+Fe3+2Al3(PO4)4(OH)5(H2O)4 · 2H2O |
| 8.DC.27 | Zincoberaunite | ZnFe3+5(PO4)4(OH)5 · 6H2O |
| 8.DC.30 | Maghrebite | MgAl2(AsO4)2(OH)2 · 8H2O |
| 8.DC.30 | Ferrolaueite | Fe2+Fe3+2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Ushkovite | MgFe3+2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Laueite | Mn2+Fe3+2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Paravauxite | Fe2+Al2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Sigloite | Fe3+Al2(PO4)2(OH)3 · 7H2O |
| 8.DC.30 | Nordgauite | MnAl2(PO4)2(F,OH)2 · 5H2O |
| 8.DC.30 | Kayrobertsonite | [MnAl2(PO4)2(OH)2(H2O)4] · 2H2O |
| 8.DC.30 | Kummerite | Mn2+Fe3+Al(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Mangangordonite | Mn2+Al2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Stewartite | Mn2+Fe3+2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Gordonite | MgAl2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Kastningite | (Mn2+,Fe2+,Mg)Al2(PO4)2(OH)2 · 8H2O |
| 8.DC.30 | Pseudolaueite | Mn2+Fe3+2(PO4)2(OH)2 · 8H2O |
| 8.DC.32 | Kamarizaite | Fe3+3(AsO4)2(OH)3 · 3H2O |
| 8.DC.32 | Tinticite | Fe3+3(PO4)2(OH)3 · 3H2O |
| 8.DC.35 | Vauxite | Fe2+Al2(PO4)2(OH)2 · 6H2O |
| 8.DC.37 | Vantasselite | Al4(PO4)3(OH)3 · 9H2O |
| 8.DC.40 | Cacoxenite | Fe3+24AlO6(PO4)17(OH)12 · 75H2O |
| 8.DC.45 | Souzalite | Mg3Al4(PO4)4(OH)6 · 2H2O |
| 8.DC.45 | Gormanite | (Fe2+,Mg)3(Al,Fe3+)4(PO4)4(OH)6 · 2H2O |
| 8.DC.47 | Kingite | Al3(PO4)2F2(OH) · 7H2O |
| 8.DC.50 | Allanpringite | Fe3+3(PO4)2(OH)3 · 5H2O |
| 8.DC.50 | Fluorwavellite | Al3(PO4)2(OH)2F · 5H2O |
| 8.DC.50 | Wavellite | Al3(PO4)2(OH)3 · 5H2O |
| 8.DC.52 | Kribergite | Al5(PO4)3(SO4)(OH)4 · 4H2O |
| 8.DC.55 | Mapimite | Zn2Fe3+3(AsO4)3(OH)4 · 10H2O |
| 8.DC.57 | Ogdensburgite | Ca2Fe3+4(Zn,Mn2+)(AsO4)4(OH)6 · 6H2O |
| 8.DC.60 | Cloncurryite | Cu0.5(VO)0.5Al2(PO4)2F2 · 5H2O |
| 8.DC.60 | Nevadaite | (Cu2+,Al,V3+)6Al8(PO4)8F8(OH)2 · 22H2O |
| 8.DC.62 | Kenngottite | Mn2+3Fe3+4(PO4)4(OH)6(H2O)2 |
| 8.DC.67 | Molinelloite | Cu(H2O)(OH)V4+O(V5+O4) |
| 8.DC.70 | Whitecapsite | H16Fe2+5Fe3+14Sb3+6(AsO4)18O16 · 120H2O |
| 8.DC.75 | Heimite | PbCu2(AsO4)(OH)3 · 2H2O |
| 8.DC.80 | Lednevite | Cu[PO3(OH)] · H2O |
Fluorescence of Euchroite
Non-fluorescent.
Other Information
Notes:
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 Euchroite
mindat.org URL:
https://www.mindat.org/min-1417.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Euchroite
Reference List:
Church, A. H. (1895) A Chemical Study of Some Native Arsenates and Phosphates. Mineralogical Magazine and Journal of the Mineralogical Society, 11 (49) 1-12 doi:10.1180/minmag.1895.011.49.01
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.73
Berry, L. G. (1951) Observations on conichalcite, cornwallite, euchroite, liroconite and olivenite. American Mineralogist, 36 (5-6) 484-503
Finney, J. J. (1966) Refinement of the crystal structure of euchorite, Cu2(AsO4)(OH)3H2O. Acta Crystallographica, 21 (3) 437-440 doi:10.1107/s0365110x66003104
Eby, R. K., Hawthorne, F. C. (1989) Euchroite, a heteropolyhedral framework structure. Acta Crystallographica Section C Crystal Structure Communications, 45 (10) 1479-1482 doi:10.1107/s0108270189003148
Localities for Euchroite
Showing 34 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.
Australia | |
| Alan Melbourne |
| Munro-Smith (2006) |
Austria | |
| Kirchner et al. (2004) |
| R.Poeverlein (2016) |
| Kirchner et al. (2004) | |
| Neschen (n.d.) | |
| Poeverlein (2008) | |
| Poeverlein et al. (2010) |
| Poeverlein et al. (2010) | |
| 58. +1 other reference |
Bulgaria | |
| Mincheva-Stefanova (1968) +1 other reference |
Chile | |
| |
Czech Republic | |
| Černý |
France | |
| Weiner et al. (1998) |
Germany | |
| Weiß (1990) |
Greece | |
| |
| Kohlberger (1976) | |
Italy | |
| Vergani (2019) +1 other reference |
| Preite et al. (2007) |
Namibia | |
| Bowell et al. (2018) |
Poland | |
| Lis et al. (1986) |
Romania | |
| www.minerals-of-the-carpathians |
Russia | |
| Nenasheva et al. (2011) |
Slovakia | |
| Martin Števko |
| Majzlan et al. (2017) |
| Števko et al. (2011) |
Spain | |
| Calvo et al. (2014) |
Switzerland | |
| Stalder et al. (1998) |
| Meisser (1999) +2 other references |
USA | |
| Weiner et al. (1998) |
| AIME Pacific Southwest Mineral Industry ... |
| Holmwood (2023) |
| Dunn (1995) |
| Anthony et al +2 other references |
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Svätodušná deposit, Ľubietová, Banská Bystrica District, Banská Bystrica Region, Slovakia