Agardite-(Nd)
A valid IMA mineral species
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About Agardite-(Nd)
Formula:
NdCu6(AsO4)3(OH)6 · 3H2O
Colour:
Grass-green, greenish, greenish-blue
Lustre:
Vitreous, Silky
Hardness:
3 - 4
Crystal System:
Hexagonal
Member of:
Originally an incompletely characterised member of the Mixite Group, published without approval.
Finally approved in 2010, based on material from the Hilarion Mine, Lavrion, Greece.
Quantitative analyses are generally needed to ensure that the Mixite-group sample in question is really Nd-dominant, and not simply a Nd-rich variety.
Originally reported from Wittichen, Schenkenzell, Black Forest, Baden-Württemberg, Germany.
Finally approved in 2010, based on material from the Hilarion Mine, Lavrion, Greece.
Quantitative analyses are generally needed to ensure that the Mixite-group sample in question is really Nd-dominant, and not simply a Nd-rich variety.
Originally reported from Wittichen, Schenkenzell, Black Forest, Baden-Württemberg, Germany.
Unique Identifiers
Mindat ID:
43
Long-form identifier:
mindat:1:1:43:3
Similar Names
| Agardite | A synonym | |
| Agardite-(Ca) | A synonym of Zálesíite | |
| Agardite-(Ce) | A valid IMA mineral species | CeCu6(AsO4)3(OH)6 · 3H2O |
| Agardite-(Dy) | (Dy,La)Cu6(AsO4)3(OH)6 · 3H2O | |
| Agardite-(La) | A valid IMA mineral species | LaCu6(AsO4)3(OH)6 · 3H2O |
| Agardite-(Y) | A valid IMA mineral species | YCu6(AsO4)3(OH)6 · 3H2O |
IMA Classification of Agardite-(Nd)
Classification of Agardite-(Nd)
8.DL.15
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
L : With large and medium-sized cations, (OH, etc.):RO4 = 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
L : With large and medium-sized cations, (OH, etc.):RO4 = 2:1
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 |
|---|---|---|
| Agr-Nd | 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 Agardite-(Nd)
Vitreous, Silky
Transparency:
Transparent
Comment:
Vitreous in crystals and silky in aggregates.
Colour:
Grass-green, greenish, greenish-blue
Streak:
White, greenish white
Hardness:
3 - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven
Comment:
Density could not be measured.
Optical Data of Agardite-(Nd)
Type:
Uniaxial (+)
RI values:
nω = 1.709 - 1.712 nε = 1.775 - 1.780
Max. Birefringence:
δ = 0.066 - 0.068
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Strong
Comments:
O = pale turquoise; E = bright green-blue.
Comments:
Absorption: E > O.
Chemistry of Agardite-(Nd)
Mindat Formula:
NdCu6(AsO4)3(OH)6 · 3H2O
Element Weights:
Crystallography of Agardite-(Nd)
Crystal System:
Hexagonal
Class (H-M):
6/m - Dipyramidal
Space Group:
P63/m
Cell Parameters:
a = 13.548(8) Å, c = 5.894(6) Å
Ratio:
a:c = 1 : 0.435
Unit Cell V:
936.90 ų (Calculated from Unit Cell)
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.70 Å | (100) |
| 4.443 Å | (22) |
| 3.545 Å | (18) |
| 3.255 Å | (8) |
| 2.935 Å | (18) |
| 2.695 Å | (13) |
| 2.559 Å | (10) |
| 2.453 Å | (30) |
Comments:
Hilarion Mine, Kamariza Mines, Attica, Greece. The data are from Pekov et al. (2011).
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 Agardite-(Nd)
General Appearance of Type Material:
Thin, acicular to hair-like crystals up to 0.5 mm long and up to 5 μm thick, elongate along [001], with a hexagonal cross section. Also occurs with agardite-(Y) and/or agardite-(La) to form rims, up to 3 μm thick, in zoned acicular crystals, up to 0.015 × 1.2 mm, with a core of zálesíite. Typically in sprays or radiating clusters up to 2 mm.
Place of Conservation of Type Material:
Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow, Russia, number 4020/1.
Geological Setting of Type Material:
In cavities of an oxidized ore (primarily goethite) and in cracks of supergene altered mica schist.
Associated Minerals at Type Locality:
Synonyms of Agardite-(Nd)
Other Language Names for Agardite-(Nd)
Dutch:Agardiet-(Nd)
French:Agardite-(Nd)
German:Agardit-(Nd)
Japanese:ネオジムアガアド石
Norwegian:Agarditt-(Nd)
Russian:Агардит-(Nd)
Simplified Chinese:砷钕铜石
Traditional Chinese:砷釹銅石
Relationship of Agardite-(Nd) to other Species
Member of:
Other Members of Mixite Group:
| Agardite-(Ce) | CeCu6(AsO4)3(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Agardite-(La) | LaCu6(AsO4)3(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Agardite-(Y) | YCu6(AsO4)3(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Calciopetersite | CaCu6(PO4)2(PO3OH)(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Goudeyite | AlCu6(AsO4)3(OH)6 · 3H2O | Hex. |
| Mixite | BiCu6(AsO4)3(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Petersite-(Ce) | CeCu6(PO4)3(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Petersite-(La) | LaCu6(PO4)3(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Petersite-(Y) | YCu6(PO4)3(OH)6 · 3H2O | Hex. |
| Plumboagardite | PbCu6(AsO4)2(AsO3OH)(OH)6 · 3H2O | Hex. 6/m : P63/m |
| Zálesíite | CaCu6(AsO4)2(AsO3OH)(OH)6 · 3H2O | Hex. 6/m : P63/m |
Common Associates
Associations Based on Photo Data:
| 16 photos of Agardite-(Nd) associated with Conichalcite | CaCu(AsO4)(OH) |
| 3 photos of Agardite-(Nd) associated with Adamite | Zn2(AsO4)(OH) |
| 2 photos of Agardite-(Nd) associated with Brochantite | Cu4(SO4)(OH)6 |
| 2 photos of Agardite-(Nd) associated with Malachite | Cu2(CO3)(OH)2 |
| 1 photo of Agardite-(Nd) associated with Allophane | (Al2O3)(SiO2)1.3-2 · 2.5-3H2O |
| 1 photo of Agardite-(Nd) associated with Libethenite | Cu2(PO4)(OH) |
| 1 photo of Agardite-(Nd) associated with Pseudomalachite | Cu5(PO4)2(OH)4 |
| 1 photo of Agardite-(Nd) associated with 'Chalcedony' | SiO2 |
| 1 photo of Agardite-(Nd) associated with 'Copper-bearing Adamite' | (Zn,Cu)2AsO4OH |
| 1 photo of Agardite-(Nd) associated with Agardite-(La) | LaCu6(AsO4)3(OH)6 · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 8.DL.05 | Foggite | CaAl(PO4)(OH)2 · H2O |
| 8.DL.10 | Fluorowardite | NaAl3(PO4)2F2(OH)2(H2O)2 |
| 8.DL.10 | Wardite | NaAl3(PO4)2(OH)4 · 2H2O |
| 8.DL.10 | Millisite | (Na,K)CaAl6(PO4)4(OH)9 · 3H2O |
| 8.DL.10 | Cyrilovite | NaFe3+3(PO4)2(OH)4 · 2H2O |
| 8.DL.15 | Petersite-(Ce) | CeCu6(PO4)3(OH)6 · 3H2O |
| 8.DL.15 | Agardite-(Y) | YCu6(AsO4)3(OH)6 · 3H2O |
| 8.DL.15 | Agardite-(Ce) | CeCu6(AsO4)3(OH)6 · 3H2O |
| 8.DL.15 | 'Agardite-(Dy)' | (Dy,La)Cu6(AsO4)3(OH)6 · 3H2O |
| 8.DL.15 | Agardite-(La) | LaCu6(AsO4)3(OH)6 · 3H2O |
| 8.DL.15 | Petersite-(Y) | YCu6(PO4)3(OH)6 · 3H2O |
| 8.DL.15 | Zálesíite | CaCu6(AsO4)2(AsO3OH)(OH)6 · 3H2O |
| 8.DL.15 | Mixite | BiCu6(AsO4)3(OH)6 · 3H2O |
| 8.DL.15 | Petersite-(La) | LaCu6(PO4)3(OH)6 · 3H2O |
| 8.DL.15 | Goudeyite | AlCu6(AsO4)3(OH)6 · 3H2O |
| 8.DL.15 | Calciopetersite | CaCu6(PO4)2(PO3OH)(OH)6 · 3H2O |
| 8.DL.15 | Plumboagardite | PbCu6(AsO4)2(AsO3OH)(OH)6 · 3H2O |
| 8.DL.20 | Dugganite | Pb3Zn3(AsO4)2(TeO6) |
| 8.DL.20 | Wallkilldellite | Ca2Mn2+3(AsO4)2(OH)4 · 9H2O |
| 8.DL.20 | Wallkilldellite-(Fe) | (Ca,Cu)4Fe2+6(AsO4,SiO4)4(OH,O)8 · 18H2O |
| 8.DL.20 | Cheremnykhite | Pb3Zn3(VO4)2(TeO6) |
| 8.DL.20 | Kuksite | Pb3Zn3(PO4)2(TeO6) |
| 8.DL.25 | Angastonite | CaMgAl2(PO4)2(OH)4 · 7H2O |
| 8.DL.30 | Långbanshyttanite | Pb2Mn2Mg(AsO4)2(OH)4 · 6H2O |
Fluorescence of Agardite-(Nd)
Not fluorescent.
Other Information
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 Agardite-(Nd)
mindat.org URL:
https://www.mindat.org/min-43.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Agardite-(Nd)
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) New minerals and nomenclature modifications approved in 2010, CNMNC Newsletter No 7. Mineralogical Magazine, 75 (1) 27-31 doi:10.1180/minmag.2011.075.1.27
Pekov, I. V., Chukanov, N. V., Zadov, A. E., Voudouris, P., Magganas, A., Katerinopoulos, A. (2011) Agardite-(Nd) NdCu6(AsO4)3(OH)6·3H2O from the Hilarion Mine, Lavrion, Greece: mineral description and chemical relations with other members of the agardite-zálesíite solid-solution system. Journal of GEOsciences, 56 (3) 249-255
Localities for Agardite-(Nd)
Showing 25 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 | |
| Leverett et al. (2003) |
| Downes et al. (2006) |
Austria | |
| Kolitsch (2014) |
| Auer (2025) |
| Exel (1993) +1 other reference |
Bulgaria | |
| Kunov +2 other references |
France | |
| |
Germany | |
| [Wittern (1995) +1 other reference |
| Göb et al. (2011) |
| Walenta et al. (2004) |
| Walenta (1992) | |
| Walenta (1992) | |
| Walenta (1992) |
| Walenta (1992) |
| Walenta (1992) +1 other reference |
Greece (TL) | |
| Williams et al. (2011) +1 other reference |
Italy | |
| Collected by F. Castellaro and probed ... |
| Guastoni et al. (2017) |
| Guastoni et al. (2017) |
| Guastoni et al. (2017) | |
| Gasparetto et al. (2026) |
UK | |
| Embrey (1978) +1 other reference |
USA | |
| Castor et al. (2004) |
| Dakota Matrix - Tom Loomis | |
| Castor et al. (2004) |
Quick NavTopAbout Agardite-(Nd)Unique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Hilarion Mine, Kamariza Mines, Agios Konstantinos, Lavreotiki, East Attica, Attica, Greece