Itoigawaite Mineral Data

General Itoigawaite Information

Chemical Formula:

SrAl2Si2O7(OH)2•(H2O)

Composition:

Molecular Weight = 361.78 gm

Strontium 24.22 % Sr 28.64 % SrO

Aluminum 14.92 % Al 28.18 % Al₂O₃

Silicon 15.53 % Si 33.22 % SiO₂

Hydrogen 1.11 % H 9.96 % H₂O

Oxygen 44.22 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

SrAl₂Si₂O₇(OH)₂•(H₂O)

Environment:

As a veinlet in jadeitite boulders. A member of the lawsonite group

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

On the seashore of Oyashirazu, about 15 km WSW of Itoigawa Station, Itoigawa-Ohmi district, Niigata-ken Prefecture, Japan. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

IMA1998-034

Itoigawaite Crystallography

Axial Ratios:

a:b:c =0.6742:1:1.4778

Cell Dimensions:

a = 6.031, b = 8.945, c = 13.219, Z = 4; V = 713.13 Den(Calc)= 3.37

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: C mcm

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

By Intensity(I/I_o): 2.68(1), 3.31(0.85), 4.26(0.85),2.45(0.75), 2.5(0.75), 2.63(0.75), 2.75(0.75), 4.68(0.75),

Physical Properties of Itoigawaite

Cleavage:

{???} Good

Color:

Blue.

Diaphaneity:

Transparent

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

5-5.5 - Apatite-Knife Blade

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Itoigawaite

Gladstone-Dale:

CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2004,KC= 0.2028
Ncalc = 1.68

Optical Data:

Biaxial (+), a=1.664, b=1.674, g=1.688, bire=0.0240

Calculated Properties of Itoigawaite

Electron Density:

Bulk Density (Electron Density)=3.28 gm/cc
note: Specific Gravity of Itoigawaite =3.37 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Itoigawaite= 27.38 barns/electron
U=PE_Itoigawaite x rElectron Density= 89.78 barns/cc.

Radioactivity:

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

Itoigawaite Classification

Dana Class:

56.02.03.05 (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O

(56.02)with cations in [4] and/or >[4] coordination

(56.02.03)Lawsonite - Ilvaite group

56.02.03.01 Lawsonite CaAl2Si2O7(OH)2•(H2O) Ccmm 2/m 2/m 2/m

56.02.03.02 Hennomartinite SrMn2Si2O7(OH)2•(H2O) C mcm 2/m 2/m 2/m

56.02.03.03 Ilvaite CaFe2FeSi2O7O(OH) Pbnm 2/m 2/m 2/m

56.02.03.04 Noelbensonite! BaMn2(Si2O7)(OH)2•(H2O) C mcm 2/m 2/m 2/m

56.02.03.05 Itoigawaite! SrAl2Si2O7(OH)2•(H2O) C mcm 2/m 2/m 2/m

56.02.03.06 Manganilvaite! CaFeFe(Mn,Fe)(Si2O7)O(OH) P 2₁/a 2/m

Strunz Class:

09.BE.05 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BE -Si2O7 groups with additional anions;

09.BE.05 Hennomartinite SrMn2Si2O7(OH)2•(H2O) C mcm 2/m 2/m 2/m

09.BE.05 Lawsonite CaAl2Si2O7(OH)2•(H2O) Ccmm 2/m 2/m 2/m

09.BE.05 Noelbensonite! BaMn2(Si2O7)(OH)2•(H2O) C mcm 2/m 2/m 2/m

09.BE.05 Itoigawaite! SrAl2Si2O7(OH)2•(H2O) C mcm 2/m 2/m 2/m

Other Itoigawaite Information

References:

NAME( MinRec, Vol 31, No 4) PHYS. PROP.(MinRec, Vol 31, No 4) OPTIC PROP.(MinRec, Vol 31, No 4)

See Also:

Links to other databases for Itoigawaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Itoigawaite

SrAl2Si2O7(OH)2•(H2O)
Dana No: 56.02.03.05 Strunz No: 09.BE.05
Locality:

Notes:

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