Iddingsite Mineral Data

General Iddingsite Information

Chemical Formula:

MgO.Fe2O3.3SiO2•4(H2O)

Composition:

Molecular Weight = 452.31 gm

Magnesium 5.37 % Mg 8.91 % MgO

Iron 24.69 % Fe 31.77 % FeO

Silicon 18.63 % Si 39.85 % SiO₂

Hydrogen 1.78 % H 15.93 % H₂O

Oxygen 49.52 % O

______ ______

100.00 % 96.46 % = TOTAL OXIDE

Empirical Formula:

MgFe²⁺₂Si₃O₁₀•4(H₂O)

Environment:

Alteration of olivine. Iddinsite is a mixture of various hydrous silicates of iron and magnesium.

IMA Status:

Discredited IMA 1966 - Valid Species (Pre-IMA) 1925

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named for Joseph Paxson Iddings (1857-1920), American petrologist, U.S. Geological Survey.

Iddingsite Image

Images:

Iddingsite

Comments: Red iddingsite with green olivine. Iddingsite alteration of olivine commonly seen in thin-sections is actually a fine-grained mixture of goethite+quartz+chlorite.
Location: Amboy, San Bernadino County, California, USA. Scale: Specimen Size 5x5x3 cm.
© John Betts - Fine Minerals

Iddingsite Crystallography

Crystal System:

Orthorhombic

Physical Properties of Iddingsite

Cleavage:

{???} Perfect

Color:

Brown.

Density:

2.5 - 2.8, Average = 2.65

Habit:

Foliated - Two dimensional platy forms.

Hardness:

3 - Calcite

Luminescence:

Non-fluorescent.

Optical Properties of Iddingsite

Gladstone-Dale:

CI meas= -0.275 (Poor) - where the CI = (1-KPDmeas/KC)
KPDmeas= 0.2736,KC= 0.2146
Ncalc = 1.54 - 1.6

Optical Data:

Biaxial (-), a=1.67-1.73, b=1.7-1.76, g=1.72-1.77, bire=0.0400-0.0500

Calculated Properties of Iddingsite

Electron Density:

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

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Iddingsite= 8.08 barns/electron
U=PE_Iddingsite x rElectron Density= 21.41 barns/cc.

Radioactivity:

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

Iddingsite Classification

Dana Class:

78.00.00.00 (78)Unclassified Silicate Minerals

(78.00)Without Dana Classification Numbers

(78.00.00)Unclassified Silicate

78.00.00.00 Almbosite? Fe5Fe4V4Si3O27 Ortho ? Ortho

78.00.00.00 Chelyabinskite* (Ca,Mg)3Si(OH)6(SO4,CO3)2•9(H2O) Unk Ortho

78.00.00.00 Cryptophyllite K2Ca[Si4O10]•5H2O P 2₁/n 2/m

78.00.00.00 IMA2007-041T Na2[Ti4O2(OH)2(SiO4)3]•6H2O R 3m 3m

78.00.00.00 IMA2009-001 Ba5(Ca,REE,Y)22(Ti,Nb)18(SiO4)4[(PO4),(SiO4)]4(BO3)9O22[(OH),F]43(H2O)1.5 R 3 3

78.00.00.00 Iddingsite? MgO.Fe2O3.3SiO2•4(H2O) Ortho

78.00.00.00 Ivanyukite-Cu Cu[Ti4(OH)2O2(SiO4)3]•7H2O P 4 3m 4 3m

78.00.00.00 Ivanyukite-K K2[Ti4(OH)2O2(SiO4)3]•9H2O P 4 3m 4 3m

78.00.00.00 Ivanyukite-Na Na2[Ti4O2(OH)2(SiO4)3]•6H2O P 4 3m 4 3m

78.00.00.00 Plumbophyllite Pb2Si4O10•H2O P bcn 2/m 2/m 2/m

78.00.00.00 Sturtite? (Fe3)(Mn2,Ca,Mg)Si4O10(OH)3•10(H2O) None

Strunz Class:

09.HX.00 09 - SILICATES (Germanates)

09.H - Unclassified Strunz Silicates

09.HX -Unclassified Silicate

09.HX.00 Iddingsite? MgO.Fe2O3.3SiO2•4(H2O) Ortho

09.HX.00 IMA2007-041T Na2[Ti4O2(OH)2(SiO4)3]•6H2O R 3m 3m

09.HX.00 Plumbophyllite Pb2Si4O10•H2O P bcn 2/m 2/m 2/m

09.HX.00 Cryptophyllite K2Ca[Si4O10]•5H2O P 2₁/n 2/m

Other Iddingsite Information

References:

NAME( Ford32) PHYS. PROP.(Dana) OPTIC PROP.(Heinrich65)

See Also:

Links to other databases for Iddingsite :
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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Print or Cut-and-Paste your Iddingsite Specimen Label here :

Iddingsite

MgO.Fe2O3.3SiO2•4(H2O)
Dana No: 78.00.00.00 Strunz No: 09.HX.00
Locality:

Notes: