Acuminite Mineral Data

General Acuminite Information

Chemical Formula:

SrAlF4(OH)•(H2O)

Composition:

Molecular Weight = 225.62 gm

Strontium 38.84 % Sr 45.93 % SrO

Aluminum 11.96 % Al 22.60 % Al₂O₃

Hydrogen 1.34 % H 11.98 % H₂O

Oxygen 14.18 % O

Fluorine 33.68 % F 33.68 % F

- % F -14.18 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

SrAlF₄(OH)•(H₂O)

Environment:

In the Ivigtut cryolite deposit, southwestern Greenland.

IMA Status:

Approved IMA 1987

Locality:

Greenland, Ivigtut Link to MinDat.org Location Data.

Name Origin:

From the Latin acuminis, sharp point, for spear head, the characteristic shape of the crystals.

Name Pronunciation:

Acuminite + Pronunciation

Synonym:

ICSD 33830

PDF 48-1870

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Acuminite Crystallography

Axial Ratios:

a:b:c =2.5551:1:2.7538

Cell Dimensions:

a = 13.223, b = 5.175, c = 14.251, Z = 8; beta = 111.61° V = 906.64 Den(Calc)= 3.31

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): 3.5049(1), 4.7058(1), 4.7674(1),

Crystal Structure:

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Krogh Andersen E , Ploug-Sorensen G , Leonardsen E , Zeitschrift fur Kristallographie , 194 (1991) p.221-227, The structure of acuminite, a strontium aluminium fluoride mineral, Locality: Ivigtut, Greenland

Physical Properties of Acuminite

Cleavage:

{???} Perfect

Color:

Colorless.

Density:

3.295

Diaphaneity:

Transparent

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Acuminite

Optical Data:

Biaxial (+), a=1.4507, b=1.4528, g=1.4624-1.4627, bire=0.0117-0.0120, 2V(Calc)=50-52, 2V(Meas)=46-57.

Calculated Properties of Acuminite

Electron Density:

Bulk Density (Electron Density)=3.11 gm/cc
note: Specific Gravity of Acuminite =3.31 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Acuminite= 44.23 barns/electron
U=PE_Acuminite x rElectron Density= 137.56 barns/cc.

Radioactivity:

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

Acuminite Classification

Dana Class:

11.06.17.01 (11)Halide Complexes; Alumino-fluorides

(11.06)with miscellaneous formulae

(11.06.17)Dana Group

11.06.17.01 Acuminite SrAlF4(OH)•(H2O) C 2/c 2/m

Strunz Class:

03.CC.10 03 - HALIDES

03.C - Complex Halides

03.CC -Soro-aluminofluorides

03.CC.10 Acuminite SrAlF4(OH)•(H2O) C 2/c 2/m

03.CC.10 Tikhonenkovite SrAl(OH)F4•(H2O) Unk Mono

Other Acuminite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Am.Min.,Vol.73,p1492,1988) OPTIC PROP.(Am.Min.,Vol.73,p1492,1988)

See Also:

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

Acuminite

SrAlF4(OH)•(H2O)
Dana No: 11.06.17.01 Strunz No: 03.CC.10
Locality:

Notes: