Ardennite-(As) (original) (raw)

A valid IMA mineral species - grandfathered

About Ardennite-(As)Hide

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Formula:

Mn2+4Al4(AlMg)(AsO4)(SiO4)2(Si3O10)(OH)6

Specific Gravity:

3.69 - 3.75

Crystal System:

Orthorhombic

Name:

For the type locality in the Ardennes Mountains, Belgium. The original name was simply ardennite, without the suffix. The approval of ardennite-(V) led the IMA renaming this species in 2007 with the addition of the suffix.

The AsO4-analogue of (the less common) ardennite-(V). Both form a a complete solid-solution series and crystals may be zoned, with variable As:V ratios; additionally Si may replace As.

Structurally closely related to lavoisierite.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:322:5

e0604f98-7ebf-4a04-a584-f879b83a2c5a

IMA Classification of Ardennite-(As)Hide

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Approved, 'Grandfathered' (first described prior to 1959)

IMA status notes:

Renamed by the IMA

Approval history:

Renamed from ardennite to ardennite-(As) in 2007.

Type description reference:

Classification of Ardennite-(As)Hide

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9.BJ.40

9 : SILICATES (Germanates)
B : Sorosilicates
J : Sorosilicates with Si3O10, Si4O11, etc. anions; cations in octahedral [6] and greater coordination

58.3.1.1

58 : SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
3 : Insular, Mixed, Single, and Larger Tetrahedral Groups with insular single and triple groups (n=1, 3)

17.7.4

17 : Silicates Containing other Anions
7 : Silicates with vanadate, arsenate or antimonate

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of Ardennite-(As)Hide

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Cleavage:

Perfect
Perfect on {010}, distinct on {110}

Fracture:

Irregular/Uneven, Sub-Conchoidal

Density:

3.69 - 3.75 g/cm3 (Measured) 3.74 g/cm3 (Calculated)

Optical Data of Ardennite-(As)Hide

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RI values:

_n_α = 1.759 _n_β = 1.740 - 1.780 _n_γ = 1.774

Birefringence:

Older literature reports 0.15-0.20; more recent observations give values ranging from 0.015(1) to 0.0181(2).

δ = 0.015

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Dispersion:

strong (but contradictory data are reported; see comments below)

Comments:

X= dark brownish yellow
Y= golden yellow
X= pale yellow

However, more recent observations indicate only weak pleochroism, in medium brownish-yellow (see comments below).

Comments:

The reported older literature optical data for ardennite-(As) differ markedly from more recent observations (see [https://www.rockptx.com/fkm-351-to-fkm-375/#FKM-372]), and appear to be at least partially incorrect. The missing data and apparent inconsistencies are described in more detail here.

In addition to the discrepancy in reported birefringence noted above, older literature reports 2Vz° = 0-70°; more recent observations more specifically give 2Vz° = 30(5)° for material from Salmchâteau, although Bermanec et al., 2021 report 2Vx° = 49(1)° for material from Nežilovo (hence the latter material would be B(-)).

Values for nα and nγ are not reported from the older literature, and so are estimated here for material from Salmchâteau sample FKM-372 from the observed δ and 2V°. The nα and nβ values for Nežilovo material reported by Bermanec et al., 2021 are implausibly low (nα = 1.537(2) and nβ = 1.579(1)) and appear to be erroneous (and also markedly differ from the analogous values obtained by Barresi et al., 2007 for an Italian example of the related mineral ardennite-(V).)

Dispersion appears variable, with older literature reporting "strong", and also Bermanec et al., 2021 reporting "strong" with v > r for the Nežilovo material. But Barresi et al., 2007 do not observe any notable dispersion in their Italian ardennite-(V), and similarly, the FKM-372 Salmchâteau ardennite-(As) shows only at best very weak dispersion, and when discernible r > v.

In contrast to the older literature, all the recent work on both the As-dominant and V-dominant species note only weak pleochroism, in tones of yellow or brownish-yellow.

Chemistry of Ardennite-(As)Hide

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Mindat Formula:

Mn2+4Al4(AlMg)(AsO4)(SiO4)2(Si3O10)(OH)6

Crystallography of Ardennite-(As)Hide

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Crystal System:

Orthorhombic

Class (H-M):

m m m _(_2/_m_2/_m_2/m ) - Dipyramidal

Cell Parameters:

a = 8.7126(8) Å, b = 18.5124(11) Å, c = 5.8108(8) Å

Ratio:

a:b:c = 0.471 : 1 : 0.314

Unit Cell V:

937.23 ų (Calculated from Unit Cell)

Morphology:

Prismatic, radiating fibrous groups.

Comment:

Space Group: Pnmm

Crystallographic forms of Ardennite-(As)Hide

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Crystal Atlas:

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Crystal StructureHide

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ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0009340	Ardennite-(As)	Donnay G, Allmann R (1968) Si3O10 groups in the crystal structure of ardennite Acta Crystallographica B24 845-855		1968	0	293
0019900	Ardennite-(As)	Nagashima M, Armbruster T (2010) Ardennite, tiragalloite and medaite: structural control of (As5+,V5+,Si4+)O4 tetrahedra in silicates Mineralogical Magazine 74 55-71	2010	Salm-Chateau, Ardennes, Belgium	0	293
0019901	Ardennite-(As)	Nagashima M, Armbruster T (2010) Ardennite, tiragalloite and medaite: structural control of (As5+,V5+,Si4+)O4 tetrahedra in silicates Mineralogical Magazine 74 55-71	2010	Vernetto mine, Val Lanzo, Torino, Piedmont, Italy	0	293

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Geological EnvironmentHide

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Geological Setting:

Highly oxidized, Mn, Al metasediments.

Type Occurrence of Ardennite-(As)Hide

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Place of Conservation of Type Material:

Mineralogical Museum University of Wroclaw, Poland.
Musée de Minéralogie, Ecole des Mines de Paris (originally as 'dewalquite').

Geological Setting of Type Material:

Pegmatites and quartz veins in schist

Reference:

von Lasaulx, A. (1872) Ardennit, ein neues Mineral. Neues Jahrbuch für Mineralogie, Geologie und Paläontologie, 930-934.

Synonyms of Ardennite-(As)Hide

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Other Language Names for Ardennite-(As)Hide

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Relationship of Ardennite-(As) to other SpeciesHide

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Other Members of this group:

Common AssociatesHide

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Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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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 Ardennite-(As)Hide

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References for Ardennite-(As)Hide

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Reference List:

Bermanec, M., Chukanov, N.V., Boev, I., Šturman, B.D., Zebec, V. and Bermanec, V. (2021) Ardennite-bearing mineral association related to sulfide-free ores with chalcophile metals at Nežilovo, Pelagonian Massif, North Macedonia. European Journal of Mineralogy, 33, 433-445. https://doi.org/10.5194/ejm-33-433-2021

Depret, M., Hatert, F., Blondieau, M., Puccio, S., Erambert, M. M. L., Dal Bo, F., Bomal, F. (2024) Crystal chemistry of Belgian ardennites. European Journal of Mineralogy, 36 (4). 687-708 doi:10.5194/ejm-36-687-2024

Localities for Ardennite-(As)Hide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.