Armstrongite
A valid IMA mineral species
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About Armstrongite
Neil Armstrong
Formula:
CaZr[Si6O15] · 3H2O
Colour:
Dark to light brown
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.562 - 2.593
Crystal System:
Monoclinic
Name:
Named after Neil Alden Armstrong (5 August 1930, Wapakoneta, Ohio, USA - 25 August 2012, Cincinnati, Ohio, USA), American astronaut and aeronautical engineer. He was the first person to walk on the Moon.
This page provides mineralogical data about Armstrongite.
Unique Identifiers
Mindat ID:
344
Long-form identifier:
mindat:1:1:344:7
GUID
(UUID V4):
(UUID V4):
a11792b5-a5b9-46c4-a2d2-6dfc44ec74c4
IMA Classification of Armstrongite
Approved
IMA Formula:
CaZr(Si6O15) · 2H2O
First published:
1973
Classification of Armstrongite
9.EA.35
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
72.5.4.1
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
5 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with corrugated and complex layers
72 : PHYLLOSILICATES Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings
5 : Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings with corrugated and complex layers
14.10.22
14 : Silicates not Containing Aluminum
10 : Silicates of Zr or Hf
14 : Silicates not Containing Aluminum
10 : Silicates of Zr or Hf
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 |
|---|---|---|
| Asg | 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 Armstrongite
Vitreous
Transparency:
Translucent
Colour:
Dark to light brown
Streak:
Brownish white
Hardness:
4½ on Mohs scale
Hardness:
VHN100=310 - 330 - Vickers
Tenacity:
Very brittle
Cleavage:
Very Good
Perfect on {001}
Good on {100}
Perfect on {001}
Good on {100}
Density:
2.562 - 2.593 g/cm3 (Measured) 2.71 g/cm3 (Calculated)
Optical Data of Armstrongite
Type:
Biaxial (-)
RI values:
nα = 1.563 nβ = 1.569 nγ = 1.573
Max Birefringence:
δ = 0.010
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:
strong r < v
Chemistry of Armstrongite
Mindat Formula:
CaZr[Si6O15] · 3H2O
Common Impurities:
Ti,Al,Y,TR,Fe,Mg,Na,K
Crystallography of Armstrongite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 14.04 Å, b = 14.16 Å, c = 7.81 Å
β = 109.55°
β = 109.55°
Ratio:
a:b:c = 0.992 : 1 : 0.552
Unit Cell V:
1,463.17 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals to 2cm, aggregates
Twinning:
Polysynthetic, by rotation on [100]
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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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) |
|---|---|---|---|---|---|---|---|
| 0020417 | Armstrongite | Mesto E, Kaneva E, Schingaro E, Vladykin N, Lacalamita M, Scordari F (2014) Armstrongite from Khan Bogdo (Mongolia): Crystal structure determination and implications for zeolite-like cation exchange properties American Mineralogist 99 2424-2432 | 2014 | Khan Bogdo deposit, southern Gobi Desert, Gobi, Mongolia | 0 | 293 | |
| 0019061 | Armstrongite | Kabalov Y K, Zubkova N V, Pushcharovsky D Y, Schneider J, Sapozhnikov A N (2000) Powder Rietveld refinement of armstrongite, CaZr[Si6O15]*3H2O Zeitschrift fur Kristallographie 215 757-761 | 2000 | granite pegmatites and alkaline granites in Mongolia | 0 | 293 | |
| 0014184 | Armstrongite | Kashaev A A, Sapozhnikov A N (1978) Crystal structure of armstrongite Kristallografiya 23 956-961 | 1978 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.26 Å | (100) |
| 3.05 Å | (100) |
| 6.60 Å | (90) |
| 3.80 Å | (90) |
| 7.05 Å | (50) |
| 2.995 Å | (50) |
| 1.947 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Geological Setting:
Alkalic granites
Type Occurrence of Armstrongite
General Appearance of Type Material:
As columnar crystals elongated along [010], to 2 cm, and as tangled-fibrous aggregates
Place of Conservation of Type Material:
A.E. Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia.
Geological Setting of Type Material:
In schlieren of alkalic granite pegmatite, at the contact of arfvedsonite-bearing granite with xenoliths of felsic volcanic rock.
Associated Minerals at Type Locality:
Reference:
Vladykin, N.V., Kovalenko, V.I., Kashaev, A.A., Sapozhnikov, A.N., Pisarskaya, V.A. (1973) A new silicate of calcium and zirconium – armstrongite. Doklady Akademii Nauk SSSR: 209: 1185-1188.
Synonyms of Armstrongite
Other Language Names for Armstrongite
Common Associates
Associated Minerals Based on Photo Data:
| 14 photos of Armstrongite associated with Aegirine | NaFe3+Si2O6 |
| 4 photos of Armstrongite associated with Quartz | SiO2 |
| 3 photos of Armstrongite associated with Orthoclase | K(AlSi3O8) |
| 2 photos of Armstrongite associated with Gittinsite | CaZrSi2O7 |
| 1 photo of Armstrongite associated with Thorite | Th(SiO4) |
| 1 photo of Armstrongite associated with Calcium-bearing Elpidite | (Na,Ca)2ZrSi6O15 · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 9.EA. | Bussyite-(Y) | (Y,REE,Ca)3(Na,Ca)6MnSi9Be5(O,OH,F)34 |
| 9.EA. | Fluorapophyllite-(NH₄) | NH4Ca4(Si8O20)F · 8H2O |
| 9.EA. | Hydroxymcglassonite-(K) | KSr4Si8O20(OH) · 8H2O |
| 9.EA.05 | Cuprorivaite | CaCuSi4O10 |
| 9.EA.05 | Gillespite | BaFe2+Si4O10 |
| 9.EA.05 | Effenbergerite | BaCuSi4O10 |
| 9.EA.05 | Wesselsite | SrCuSi4O10 |
| 9.EA.07 | Fluorapophyllite-(Cs) | CsCa4(Si8O20)F · 8H2O |
| 9.EA.10 | Ekanite | Ca2ThSi8O20 |
| 9.EA.15 | Fluorapophyllite-(K) | KCa4(Si8O20)(F,OH) · 8H2O |
| 9.EA.15 | Hydroxyapophyllite-(K) | KCa4(Si8O20)(OH,F) · 8H2O |
| 9.EA.15 | Fluorapophyllite-(Na) | NaCa4(Si8O20)F · 8H2O |
| 9.EA.20 | Magadiite | Na2Si14O29 · 11H2O |
| 9.EA.25 | Dalyite | K2ZrSi6O15 |
| 9.EA.25 | Davanite | K2TiSi6O15 |
| 9.EA.30 | Sazhinite-(Ce) | Na2CeSi6O14 · 6H2O |
| 9.EA.30 | Sazhinite-(La) | Na3La[Si6O15] · 2H2O |
| 9.EA.40 | Okenite | Ca10Si18O46 · 18H2O |
| 9.EA.45 | Nekoite | Ca3Si6O15 · 7H2O |
| 9.EA.45 | Perettiite-(Y) | Y2Mn4FeSi2B8O24 |
| 9.EA.45 | Badakhshanite-(Y) | Y2Mn4Al(Si2B7BeO24) |
| 9.EA.47 | Shlykovite | KCa[Si4O9(OH)] · 3H2O |
| 9.EA.50 | Cavansite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.50 | Diegogattaite | Na2CaCu2Si8O20 · H2O |
| 9.EA.52 | Yangite | PbMnSi3O8 · H2O |
| 9.EA.55 | Pentagonite | Ca(VO)Si4O10 · 4H2O |
| 9.EA.60 | Penkvilksite | Na4Ti2Si8O22 · 4H2O |
| 9.EA.60 | Tumchaite | Na2Zr(Si4O11) · 2H2O |
| 9.EA.65 | Nabesite | Na2BeSi4O10 · 4H2O |
| 9.EA.70 | Ajoite | (K,Na)Cu7AlSi9O24(OH)6 · 3H2O |
| 9.EA.75 | Zeravshanite | Na2Cs4Zr3[Si18O45]*2H2O |
| 9.EA.80 | Bussyite-(Ce) | (Ce,REE)3(Na,H2O)6MnSi9Be5(O,OH)30F4 |
| 9.EA.85 | Plumbophyllite | Pb2Si4O10 · H2O |
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 Armstrongite
mindat.org URL:
https://www.mindat.org/min-344.html
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References for Armstrongite
Reference List:
Localities for Armstrongite
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 | |
| www.australianrareearths.com (n.d.) |
Canada | |
| Mineralogical Society of America - ... |
| Powder Diffraction Jour. v.2 no.1 +3 other references | |
Greece | |
| Kapsiotis et al. (2016) |
Mongolia | |
| Kynicky et al. (2018) |
| U. Kempe et al. (1999) |
| J Kynický et al. (2009) +4 other references |
| Vladykin N.V. et al. (1981) |
Quick NavTopAbout ArmstrongiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Khan Bogd Peralkaline Granite, Khanbogd District, Ömnögovi Province, Mongolia