Armstrongite Mineral Data

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.

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 - SphenoidalH-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),

Crystal Structure:

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Kashaev A A , Sapozhnikov A N , Kristallografiya , 23 (1978) p.956-961, Crystal structure of armstrongite

Physical Properties of Armstrongite

Cleavage:

[001] Perfect, [100] Distinct

Color:

Light brown, Reddish brown.

Density:

2.7 - 2.71, Average = 2.7

Diaphaniety:

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

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:

r_electron=2.65 gm/cc
note: r_Armstrongite=2.68 gm/cc.

Fermion Index

Fermion Index = 0.03081
Boson Index = 0.96919

Photoelectric:

PE_Armstrongite= 21.90 barns/electron
U=PE_Armstrongite x r_electron= 58.12 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Armstrongite is Not Radioactive

Armstrongite Classification

Dana Class:

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

(72.5)with corrugated and complex layers

(72.5.4)Elpidite/armstrongite

72.5.4.1 Armstrongite CaZrSi6O15·3(H2O) C 2 2

72.5.4.2 Elpidite Na2ZrSi6O15·3(H2O) Pb21m mm2

Strunz Class:

VIII/H.34-70 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica minerals with other simple layers, [Si6O15]6- and others

VIII/H.34 - Gyrolite series

VIII/H.34-10 Minehillite (K,Na)2-3Ca28(Zn4Al4Si40)O112(OH)16 P 6₃/mmm, P 62c, or P 6₃mc Hex

VIII/H.34-20 Truscottite (Ca,Mn)14Si24O58(OH)8·2(H2O) p3 or p3 Trig

VIII/H.34-25 Orlymanite Ca4Mn3Si8O20(OH)6·2(H2O) P 3-,P 3 Trig

VIII/H.34-28 Fedorite KNa4Ca4(Al,Si)16O36(OH,F)4·6(H2O) C1 1

VIII/H.34-30 Reyerite (Na,K)4Ca14Si22Al2O58(OH)8·6(H2O) P 3 3

VIII/H.34-40 Gyrolite NaCa16Si23AlO60(OH)8·64(H2O) P 6₁ 6

VIII/H.34-45 Tungusite Ca14(OH)8(Si8O20)3Fe9(OH)14 P1 1

VIII/H.34-50 Zeophyllite Ca4Si3O8(OH,F)4·2(H2O) R 3 3

VIII/H.34-70 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)

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Armstrongite

CaZrSi6O15·3(H2O)
Dana No: 72.5.4.1 Strunz No: VIII/H.34-70
Locality:

Notes: