Gerstmannite Mineral Data

General Gerstmannite Information

Chemical Formula:

(Mg,Mn)2ZnSiO4(OH)2

Composition:

Molecular Weight = 255.41 gm

Magnesium 14.27 % Mg 23.67 % MgO

Manganese 10.75 % Mn 13.89 % MnO

Zinc 25.60 % Zn 31.87 % ZnO

Silicon 11.00 % Si 23.52 % SiO₂

Hydrogen 0.79 % H 7.05 % H₂O

Oxygen 37.58 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg_1.5Mn²⁺_0.5Zn(SiO₄)(OH)₂

Environment:

In a hydrothermal vein cutting franklinite-willemite ore in a metamorphosed stratiform zinc orebody.

IMA Status:

Approved IMA 1977

Locality:

Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Ewald Gerstmann (1918- ), mineral collector of Franklin, New Jersey, USA.

Name Pronunciation:

Gerstmannite + Pronunciation

Synonym:

ICSD 100142

PDF 29-867

Gerstmannite Crystallography

Axial Ratios:

a:b:c =0.4388:1:0.3351

Cell Dimensions:

a = 8.185, b = 18.65, c = 6.25, Z = 8; V = 954.06 Den(Calc)= 3.56

Crystal System:

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

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

By Intensity(I/I_o): 2.598(1), 9.326(0.85), 3.418(0.8),

Physical Properties of Gerstmannite

Cleavage:

{010} Good

Color:

White, Light pink.

Density:

3.68

Diaphaneity:

Translucent to Opaque

Hardness:

4.5 - Between Fluorite and Apatite

Luster:

Vitreous - Adamantine

Streak:

white

Optical Properties of Gerstmannite

Gladstone-Dale:

CI meas= 0.089 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.059 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1863,KPDmeas= 0.1803,KC= 0.198
Ncalc = 1.7 - 1.73

Optical Data:

Biaxial (-), a=1.655, b=1.657, g=1.678, bire=0.0230, 2V(Calc)=36, 2V(Meas)=50-60.

Calculated Properties of Gerstmannite

Electron Density:

Bulk Density (Electron Density)=3.47 gm/cc
note: Specific Gravity of Gerstmannite =3.56 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Gerstmannite= 16.05 barns/electron
U=PE_Gerstmannite x rElectron Density= 55.70 barns/cc.

Radioactivity:

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

Gerstmannite Classification

Dana Class:

52.02.01.04 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.02)with cations in [4] and >[4] coordination

(52.02.01)Euclase group

52.02.01.01 Euclase BeAlSiO4(OH) P 2₁/a 2/m

52.02.01.02 Clinohedrite CaZnSiO4•(H2O) Aa m

52.02.01.03 Hodgkinsonite MnZn2SiO4(OH)2 P 2₁/c 2/m

52.02.01.04 Gerstmannite (Mg,Mn)2ZnSiO4(OH)2 Bbam 2/m 2/m 2/m

Strunz Class:

09.AE.25 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AE -Nesosilicates with additional (O,OH,F,H2O);

09.AE.25 Gerstmannite (Mg,Mn)2ZnSiO4(OH)2 Bbam 2/m 2/m 2/m

Other Gerstmannite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Gerstmannite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST

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Gerstmannite

(Mg,Mn)2ZnSiO4(OH)2
Dana No: 52.02.01.04 Strunz No: 09.AE.25
Locality:

Notes:

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