Amstallite Mineral Data

General Amstallite Information

Chemical Formula:

CaAl(Si,Al)4O8(OH)4•((H2O),Cl)

Composition:

Molecular Weight = 398.85 gm

Calcium 10.05 % Ca 14.06 % CaO

Aluminum 12.18 % Al 23.01 % Al₂O₃

Silicon 23.24 % Si 49.71 % SiO₂

Hydrogen 1.42 % H 12.65 % H₂O

Chlorine 1.78 % Cl 1.78 % Cl

- % Cl -0.40 % -O=Cl₂

Oxygen 51.35 % O

______ ______

100.00 % 100.80 % = TOTAL OXIDE

Empirical Formula:

CaAl_1.8Si_3.3O₈(OH)₄(H₂O)_0.8Cl_0.2

Environment:

In open fissures cutting pegmatitic schlieren, in hydrothermally altered graphite-bearing metamorphic rocks.

IMA Status:

Approved IMA 1987

Locality:

In the Amstall graphite quarry, Amstall, Austria. Link to MinDat.org Location Data.

Name Origin:

For the locality.

Name Pronunciation:

Amstallite + Pronunciation

Synonym:

ICSD 68350

PDF 41-1420

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Amstallite Crystallography

Axial Ratios:

a:b:c =1.6349:1:0.4506

Cell Dimensions:

a = 18.83, b = 11.517, c = 5.19, Z = 4; beta = 100.86° V = 1,105.37 Den(Calc)= 2.40

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/c

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

By Intensity(I/I_o): 9.75(1), 3.603(1), 3.816(0.9),5.43(0.7), 3.175(0.6), 4.714(0.6), 4.069(0.4),

Crystal Structure:

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Quint R , Neues Jahrbuch fur Mineralogie, Monatshefte , 1987 (1987) p.253-262, Description and crystal structure of amstallite, CaAl(OH)2[Al0.8Si3.2O8(OH)2]*[(H2O)0.8Cl0.2],, a new mineral from Amstall, Austria, Locality: Amstall, Austria

Physical Properties of Amstallite

Cleavage:

{100} Good

Color:

Colorless.

Density:

2.4

Diaphaneity:

Transparent to Translucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Amstallite

Gladstone-Dale:

CI meas= 0.027 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.027 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2229,KPDmeas= 0.2229,KC= 0.2292
Ncalc = 1.55

Optical Data:

Biaxial (+), a=1.533, b=1.534, g=1.538, bire=0.0050, 2V(Calc)=54, 2V(Meas)=57-59. Dispersion r > v weak.

Calculated Properties of Amstallite

Electron Density:

Bulk Density (Electron Density)=2.42 gm/cc
note: Specific Gravity of Amstallite =2.40 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Amstallite= 2.61 barns/electron
U=PE_Amstallite x rElectron Density= 6.31 barns/cc.

Radioactivity:

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

Amstallite Classification

Dana Class:

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

(72.01)with 4-membered rings

(72.01.04)Dana Group

72.01.04.01 Amstallite CaAl(Si,Al)4O8(OH)4•((H2O),Cl) C 2/c 2/m

72.01.04.02 Rudenkoite! Sr3Al3[(Si,Al)4O10](OH,O)8Cl2•H2O P 2/m, P 2 or Pm Mono

Strunz Class:

09.DP.25 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DP -Transitional ino-phyllosilicate structures

09.DP.25 Amstallite CaAl(Si,Al)4O8(OH)4•((H2O),Cl) C 2/c 2/m

Other Amstallite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Am.Min.,Vol.73,p1492,1988) OPTIC PROP.(Am.Min.,Vol.73,p1492,1988)

See Also:

Links to other databases for Amstallite :
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 Amstallite Specimen Label here :

Amstallite

CaAl(Si,Al)4O8(OH)4•((H2O),Cl)
Dana No: 72.01.04.01 Strunz No: 09.DP.25
Locality:

Notes: