Armstrongite Mineral Data

General Armstrongite Information

Chemical Formula:

CaZrSi6O15•3(H2O)

Composition:

Molecular Weight = 593.85 gm

Calcium 6.75 % Ca 9.44 % CaO

Zirconium 15.36 % Zr 20.75 % ZrO₂

Silicon 28.38 % Si 60.71 % SiO₂

Hydrogen 1.02 % H 9.10 % H₂O

Oxygen 48.50 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaZrSi₆O₁₅•3(H₂O)

Environment:

Not a lunar mineral. Associated with alkalic rocks.

IMA Status:

Approved IMA 1973

Locality:

TL:Khan-Bogdin massif, Mongolia. Link to MinDat.org Location Data.

Name Origin:

Named for Neil Alden Armstrong, (1930-), American astronaut, first human being on the moon's surface, Apollo 11 Lunar Mission.

Name Pronunciation:

Armstrongite + Pronunciation

Synonym:

ICSD 27752

PDF 29-395

Armstrongite Image

Images:

Armstrongite

Comments: Tan massive armstrongite aggregate in granite.
Location: Khan-Bogdo Massif, Gobi, Mongolia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Armstrongite Crystallography

Axial Ratios:

a:b:c =0.9982:1:0.5547

Cell Dimensions:

a = 14.108, b = 14.133, c = 7.84, Z = 4; beta = 109.4° V = 1,474.45 Den(Calc)= 2.68

Crystal System:

Monoclinic - Sphenoidal H-M Symbol (2) Space Group: C 2

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.05(1), 4.26(1), 6.6(0.9),

Physical Properties of Armstrongite

Cleavage:

{001} Perfect, {100} Distinct

Color:

Light brown, Reddish brown.

Density:

2.7 - 2.71, Average = 2.7

Diaphaneity:

Translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Bladed - Aggregates of thin lath-like crystals (e.g. kyanite).

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous (Glassy)

Streak:

brownish white

Optical Properties of Armstrongite

Gladstone-Dale:

CI meas= 0.049 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.04 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2121,KPDmeas= 0.2101,KC= 0.2208
Ncalc = 1.59 - 1.6

Optical Data:

Biaxial (-), a=1.563, b=1.569, g=1.573, bire=0.0100

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Armstrongite

Electron Density:

Bulk Density (Electron Density)=2.65 gm/cc
note: Specific Gravity of Armstrongite =2.68 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Armstrongite= 21.90 barns/electron
U=PE_Armstrongite x rElectron Density= 58.12 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Armstrongite is Not Radioactive

Armstrongite Classification

Dana Class:

72.05.04.01 (72)Phyllosilicate Two-Dimensional Infinite Sheets with Other Than Six-Membered Rings

(72.05)with corrugated and complex layers

(72.05.04)Elpidite/armstrongite

72.05.04.01 Armstrongite CaZrSi6O15•3(H2O) C 2 2

72.05.04.02 Elpidite Na2ZrSi6O15•3(H2O) Pb21m mm2

Strunz Class:

09.EA.35 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EA -Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings

09.EA.35 Armstrongite CaZrSi6O15•3(H2O) C 2 2

Other Armstrongite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990, AmMin Vol 86, p 1537) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Armstrongite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Armstrongite Specimen Label here :

Armstrongite

CaZrSi6O15•3(H2O)
Dana No: 72.05.04.01 Strunz No: 09.EA.35
Locality:

Notes:

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