Armenite
A valid IMA mineral species - grandfathered
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About Armenite
Formula:
Ba(H2O)2Ca2Al3[Al3Si9O30]
Colour:
Colourless, white, green
Lustre:
Vitreous
Hardness:
7½
Specific Gravity:
2.77
Crystal System:
Orthorhombic
Member of:
Name:
Named after the type locality, the Armen Mine, Kongsberg, Norway.
The type specimen was collected already in 1877 by cand. min. O. A. Corneliussen. He labelled the sample as "Epidote?". It was kept in the collection of the University of Oslo until February 1939 when it was rediscovered by Henrich Neumann, who also recognized it as a new mineral.
The type specimen was collected already in 1877 by cand. min. O. A. Corneliussen. He labelled the sample as "Epidote?". It was kept in the collection of the University of Oslo until February 1939 when it was rediscovered by Henrich Neumann, who also recognized it as a new mineral.
This page provides mineralogical data about Armenite.
Unique Identifiers
Mindat ID:
343
Long-form identifier:
mindat:1:1:343:8
Similar Names
IMA Classification of Armenite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
BaCa2(Al6Si9)O30·2H2O
First published:
1940
Classification of Armenite
9.CM.05
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
63.2.1b.1
63 : CYCLOSILICATES Condensed Rings
2 : Condensed Rings (Milarite - Osumilite group)
63 : CYCLOSILICATES Condensed Rings
2 : Condensed Rings (Milarite - Osumilite group)
16.12.12
16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn
16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn
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 |
|---|---|---|
| Amn | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Armenite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Armenite
Vitreous
Colour:
Colourless, white, green
Streak:
White
Hardness:
7½ on Mohs scale
Cleavage:
Perfect
Perfect prismatic. One distinct pinacoidal.
Perfect prismatic. One distinct pinacoidal.
Parting:
Along sector boundaries.
Density:
2.77 g/cm3 (Measured)
Optical Data of Armenite
Type:
Biaxial (-)
RI values:
nα = 1.55 nβ = 1.552 nγ = 1.556
2V:
Measured: 59° to 60°, Calculated: 72°
Max. Birefringence:
δ = 0.006
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:
Low (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
Optical Extinction:
X = c; Z = b.
Chemistry of Armenite
Mindat Formula:
Ba(H2O)2Ca2Al3[Al3Si9O30]
Element Weights:
Common Impurities:
Sr,Na,K
Crystallography of Armenite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnna
Setting:
Pnna
Cell Parameters:
a = 13.874(2) Å, b = 18.660(2) Å, c = 10.697(1) Å
Ratio:
a:b:c = 0.744 : 1 : 0.573
Unit Cell V:
2,769.33 ų (Calculated from Unit Cell)
Morphology:
Prismatic pseudohexagonal crystals.
Twinning:
The pseudohexagonal form is due to twinning along an axis parallel to the optic direction a.
Comment:
Space group is Pnna. Symmetry reduction is due to partial ordering of Si and Al. Ordering of water gives primitive orthorhombic unit cell.
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) |
|---|---|---|---|---|---|---|---|
| 0002054 | Armenite | Armbruster T (1999) Si,Al ordering in the double-ring silicate armenite, BaCa2Al6Si9O30.2H2O: A single-crystal X-ray and 29Si MAS NMR study American Mineralogist 84 92-101 | ![]() | 1999 | 0 | 293 | |
| 0001458 | Armenite | Armbruster T, Czank M (1992) H2O ordering and superstructures in armenite, BaCa2Al6Si9O30.2H2O: A single-crystal X-ray and TEM study sample from Remigny, Quebec, Canada American Mineralogist 77 422-430 | ![]() | 1992 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.86 Å | (100) |
| 3.41 Å | (90) |
| 2.91 Å | (90) |
| 6.94 Å | (80) |
| 2.78 Å | (80) |
| 4.25 Å | (65) |
| 9.31 Å | (55) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Armenite
Place of Conservation of Type Material:
National School of Mines, Paris, France; The Natural History Museum, London, England, 1947,290.
Geological Setting of Type Material:
A silver-bearing calcite-vein, Kongsberg, Norway.
Associated Minerals at Type Locality:
Other Language Names for Armenite
Relationship of Armenite to other Species
Member of:
Other Members of Osumilite Group:
| Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Aluminosugilite | KNa2Al2Li3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Berezanskite | K◻2Ti2Li3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Brannockite | K◻2Sn2Li3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Eifelite | KNa2(MgNa)Mg3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P63/mmc |
| Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Oftedalite | K◻2(ScCa)Be3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Osumilite | K◻2Fe2+2Al3[Al2Si10O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Osumilite-(Mg) | K◻2Mg2Al3[Al2Si10O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Plechovite | Ca2[K(H2O)]KBe3Si12O30 | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Poudretteite | K◻2Na2B3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Roedderite | K(◻Na)Mg2Mg3[Si12O30] | Hex. 6m2 : P62c |
| Shibkovite | K(◻K)Ca2Zn3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Sogdianite | K◻2Zr2Li3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Sugilite | KNa2Fe3+2Li3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
| 'UM1990-73-SiO:KMnNaZn' | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] | Hex. |
| 'Unnamed (Mn3+-dominant analog of Sugilite)' | KNa2Mn3+2Li3[Si12O30] | |
| Yagiite | Na◻2Mg2Al3[Al2Si10O30] | Hex. 6/mmm(6/m2/m2/m) : P6/mcc |
Common Associates
Associations Based on Photo Data:
| 6 photos of Armenite associated with Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| 4 photos of Armenite associated with Ganterite | Ba0.5(Na,K)0.5Al2(Si2.5Al1.5)O10(OH)2 |
| 3 photos of Armenite associated with Quartz | SiO2 |
| 3 photos of Armenite associated with Calcite | CaCO3 |
| 3 photos of Armenite associated with Chlorite Group | |
| 3 photos of Armenite associated with 'Thulite' | {Ca2}{Al,Mn3+3}(Si2O7)(SiO4)O(OH) |
| 1 photo of Armenite associated with Rutile | TiO2 |
Related Minerals - Strunz-mindat Grouping
| 9.CM. | Agakhanovite-(Y) | K◻2(YCa)Be3[Si12O30] |
| 9.CM. | Plechovite | Ca2[K(H2O)]KBe3Si12O30 |
| 9.CM.05 | Friedrichbeckeite | K(◻Na)Mg2(Be2Mg)[Si12O30] |
| 9.CM.05 | Laurentthomasite | K◻2Mg2(Be2Al)[Si12O30] |
| 9.CM.05 | 'UM1990-73-SiO:KMnNaZn' | K(KNa0.5◻0.5)(Mn1.5Na0.5)Zn3[Si12O30] |
| 9.CM.05 | Eifelite | KNa2(MgNa)Mg3[Si12O30] |
| 9.CM.05 | Almarudite | K◻2Mn2+2(Be2Al)[Si12O30] |
| 9.CM.05 | Merrihueite | K(◻Na)Fe2+2Fe2+3[Si12O30] |
| 9.CM.05 | Oftedalite | K◻2(ScCa)Be3[Si12O30] |
| 9.CM.05 | Roedderite | K(◻Na)Mg2Mg3[Si12O30] |
| 9.CM.05 | Shibkovite | K(◻K)Ca2Zn3[Si12O30] |
| 9.CM.05 | Sogdianite | K◻2Zr2Li3[Si12O30] |
| 9.CM.05 | Milarite | K(◻H2O)Ca2(Be2Al)[Si12O30] |
| 9.CM.05 | Berezanskite | K◻2Ti2Li3[Si12O30] |
| 9.CM.05 | Poudretteite | K◻2Na2B3[Si12O30] |
| 9.CM.05 | Darapiosite | KNa2Mn2(Zn2Li)[Si12O30] |
| 9.CM.05 | Chayesite | K◻2Mg2(Mg2Fe3+)[Si12O30] |
| 9.CM.05 | Osumilite-(Mg) | K◻2Mg2Al3[Al2Si10O30] |
| 9.CM.05 | Osumilite | K◻2Fe2+2Al3[Al2Si10O30] |
| 9.CM.05 | Sugilite | KNa2Fe3+2Li3[Si12O30] |
| 9.CM.05 | Trattnerite | ◻(◻)2Fe3+2Mg3[Si12O30] |
| 9.CM.05 | Brannockite | K◻2Sn2Li3[Si12O30] |
| 9.CM.05 | Klöchite | K◻2(Fe2+Fe3+)Zn3[Si12O30] |
| 9.CM.05 | Dusmatovite | K(K◻)Mn2+2Zn3[Si12O30] |
| 9.CM.05 | Yagiite | Na◻2Mg2Al3[Al2Si10O30] |
| 9.CM.9.CM. | Aluminosugilite | KNa2Al2Li3[Si12O30] |
| 9.CM.10 | Faizievite | K2Na(Ca6Na)Ti4Li6[Si6O18]2[Si12O30]F2 |
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 Armenite
mindat.org URL:
https://www.mindat.org/min-343.html
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References for Armenite
Reference List:
Neumann, Heinrich (1940) Armenite, a new mineral. Preliminary note. Norsk Geologisk Tidsskrift [Norwegian Journal of Geology], 19 (4). 312-313
Neumann, Henrich (1941) Armenite, a water-bearing barium-calcium-alumosilicate. Norsk Geologisk Tidsskrift [Norwegian Journal of Geology], 21 (1). 19-24
Mason, Brian (1987) Armenite from Broken Hill, Australia, with comments on calciocelsian and barium anorthite. Mineralogical Magazine, 51 (360) 317-318 doi:10.1180/minmag.1987.051.360.15
Jambor, John L.; Bladh, Kenneth W.; Ercit, T. Scott; Grice, Joel D.; Grew, Edward S. (1988) New mineral names. American Mineralogist, 73 (7-8). 927-935
Mason, Brian (1988) Armenite: correction. Mineralogical Magazine, 52 (364) 134 doi:10.1180/minmag.1988.052.364.17
Armbruster, Thomas, Czank, Michael (1992) H2O ordering and superstructures in armenite, BaCa2Al6Si9O30·2H2O: A single-crystal X-ray and TEM study. American Mineralogist, 77 (3-4) 422-430
Jambor, John L., Puziewicz, Jacek (1992) New Mineral Names. American Mineralogist, 77 (9-10) 1116-1121
Armbruster, Thomas (1999) Si, Al ordering in the double-ring silicate armenite, BaCa2Al6Si9O30.2H2O: A single-crystal X-ray and 29Si MAS NMR study. American Mineralogist, 84 (1). 92-101 doi:10.2138/am-1999-1-210
Geiger, Charles .A., Gatta, G. Diego, Xue, Xianyu, McIntyre, Garry J. (2012) A neutron/X-Ray diffraction, IR, and1H/29Si NMR Spectroscopic investigation of armenite: behavior of extra framework Ca cations and H2O molecules in microporous silicates. Zeitschrift für Kristallographie - Crystalline Materials, 227 (7) 411-426 doi:10.1524/zkri.2012.1515
Localities for Armenite
Showing 27 localities.
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 | |
| Birch BH Book +1 other reference |
| Mason (1987) | |
| Mason (1987) | |
Canada | |
| Tindle et al. (2005) |
| Pan et al. (1992) |
| Pouliot et al. (1984) +3 other references |
Cuba | |
| Torró et al. (2016) |
Czech Republic | |
| Novak et al. (2010) +2 other references |
| Mineralogical Society of America - ... |
Eswatini | |
| Roerdink et al. (2016) |
Italy | |
| Peyronel Pagliani (1958) +2 other references |
| Stara et al. (1994) |
| Cocco et al. (2022) |
Norway | |
| Bancroft et al. (2001) |
| Neumann (1941) |
Portugal | |
| Gaspar et al. (2000) +1 other reference |
Russia | |
| ... |
| Kasatkin et al. (2018) +1 other reference |
South Korea | |
| Gi Young Jeong (2006) |
| Cheong et al. (2003) |
Spain | |
| Canet et al. (2003) |
Sweden | |
| Makvandi et al. (2024) |
Switzerland | |
| Graeser (1993) +2 other references |
UK | |
| Tindle (2008) | |
| Fortey et al. (1991) +2 other references |
USA | |
| Mineralogical Society of America - ... +2 other references |
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The
Bratteskjerpet Mine, Kongsberg, Buskerud, Norway