Genthelvite Mineral Data

Genthelvite Mineral Data +

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General Genthelvite Information

Chemical Formula:

Zn4Be3(SiO4)3S

Composition:

Molecular Weight = 596.91 gm

Beryllium 4.53 % Be 12.57 % BeO

Zinc 43.82 % Zn 54.54 % ZnO

Silicon 14.12 % Si 30.20 % SiO₂

Sulfur 5.37 % S 5.37 % S^2-

- % S -2.68 % -O=S

Oxygen 32.16 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Zn₄Be₃(SiO₄)₃S

IMA Status:

Valid Species (Pre-IMA) 1944

Locality:

Cheyenne Canyon, El Paso County, Colorado, USA Link to MinDat.org Location Data.

Name Origin:

Named for Frederick August Ludwig Karl Genth (1820-1893), German-American mineralogist.

Synonym:

ICSD 201641

PDF 38-467

Genthelvite Image

Images:

Genthelvite

Comments: Pyramidal crystals of genthelvite.
Location: Mont St. Hilaire, Quebec, Canada. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Genthelvite Crystallography

Cell Dimensions:

a = 8.1206, Z = 2; V = 535.51 Den(Calc)= 3.70

Crystal System:

Isometric - HextetrahedralH-M Symbol (4 3m) Space Group: P 43n

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

By Intensity(I/I_o): 1.918(1), 2.174(1), 3.33(1),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Hassan I , Grundy H D , American Mineralogist , 70 (1985) p.186-192, The crystal structures of helvite group minerals, (MnFeZn)8(Be6Si6O24)S2

View Additional jPOWD Structure files for Genthelvite
[1]

Physical Properties of Genthelvite

Cleavage:

None

Color:

Blue green, Brown, Colorless, Green, Yellow.

Density:

3.62

Diaphaniety:

Transparent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Hardness:

6-6.5 - Orthoclase-Pyrite

Luminescence:

Phosphorescent fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Genthelvite

Gladstone-Dale:

CI meas= -0.146 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.122 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2009,KPDmeas= 0.2054,KC= 0.1792

Optical Data:

Isotropic, n=1.742-1.745.

Calculated Properties of Genthelvite

Electron Density:

r_electron=3.55 gm/cc
note: r_Genthelvite=3.70 gm/cc.

Fermion Index

Fermion Index = 0.0704
Boson Index = 0.9296

Photoelectric:

PE_Genthelvite= 22.74 barns/electron
U=PE_Genthelvite x r_electron= 80.63 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Genthelvite is Not Radioactive

Genthelvite Classification

Dana Class:

76.2.4.3 (76)Tectosilicate Al-Si Framework

(76.2)Feldspathoids and related species

(76.2.4)Helvite group

76.2.4.1 Helvite Mn4Be3(SiO4)3S P 43n 4 3m

76.2.4.2 Danalite Fe4Be3(SiO4)3S P 43n 4 3m

76.2.4.3 Genthelvite Zn4Be3(SiO4)3S P 43n 4 3m

Strunz Class:

VIII/J.12-30 VIII - Silicates

VIII/J - Tectosilicates (network) with anions unfamiliar to the tetraheders

VIII/J.12 - Sodalite group, Danalite - Genthelvite series

VIII/J.12-10 Danalite Fe4Be3(SiO4)3S P 43n 4 3m

VIII/J.12-20 Helvite Mn4Be3(SiO4)3S P 43n 4 3m

VIII/J.12-30 Genthelvite Zn4Be3(SiO4)3S P 43n 4 3m

Other Genthelvite Information

References:

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

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Print or Cut-and-Paste your Genthelvite Specimen Label here :

Genthelvite

Zn4Be3(SiO4)3S
Dana No: 76.2.4.3 Strunz No: VIII/J.12-30
Locality:

Notes: