Silhydrite Mineral Data

Silhydrite Mineral Data +

General Silhydrite Information

Chemical Formula:

3SiO2·(H2O)

Composition:

Molecular Weight = 198.27 gm

Silicon 42.50 % Si 90.91 % SiO₂

Hydrogen 1.02 % H 9.09 % H₂O

Oxygen 56.49 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

3(SiO₂)·(H₂O)

Environment:

Leached magadiite.

IMA Status:

Approved IMA 1972

Locality:

Trinity County magadiite locality, 6 miles east of Trinity Center Trinity Co., California. Link to MinDat.org Location Data.

Name Origin:

Named for its composition, a silica hydrate.

Silhydrite Image

Images:

Silhydrite

Comments: Fine grained massive silhydrite.
Location: Near Rome, Oregon, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Silhydrite Crystallography

Axial Ratios:

a:b:c =0.7722:1:0.8477

Cell Dimensions:

a = 14.519, b = 18.8, c = 15.938, Z = 28; V = 4,350.39 Den(Calc)= 2.12

Crystal System:

OrthorhombicSpace Group: P???

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

By Intensity(I/I_o): 14.5(1), 3.424(0.82), 3.143(0.35),

Physical Properties of Silhydrite

Color:

White.

Density:

2.141

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

1 - Talc

Streak:

white

Optical Properties of Silhydrite

Gladstone-Dale:

CI meas= 0.011 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2198,KPDmeas= 0.2177,KC= 0.22

Optical Data:

Biaxial (?), b=1.466

Calculated Properties of Silhydrite

Electron Density:

r_electron=2.14 gm/cc
note: r_Silhydrite=2.12 gm/cc.

Fermion Index

Fermion Index = 0.02011
Boson Index = 0.97989

Photoelectric:

PE_Silhydrite= 1.65 barns/electron
U=PE_Silhydrite x r_electron= 3.54 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Silhydrite is Not Radioactive

Silhydrite Classification

Dana Class:

75.2.4.1 (75)Tectosilicate Si Tetrahedral Frameworks

(75.2)SiO2 with H2O and organics

(75.2.4)Dana Group

75.2.4.1 Silhydrite 3SiO2·(H2O) P??? Ortho

Strunz Class:

VIII/H.39-10 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica minerals with tetrahedral-double layers and related structures

VIII/H.39 - Silhydrite - Vertumnite series

VIII/H.39-10 Silhydrite 3SiO2·(H2O) P??? Ortho

VIII/H.39-20 Magadiite NaSi7O13(OH)3·4(H2O) Unk Mono

VIII/H.39-30 Stratlingite Ca2Al[(OH)6AlSiO2-3(OH)4-3]·2,5(H2O) R 3m 3 2/m

VIII/H.39-40 Vertumnite Ca8Al4(Al4Si5)O12[(OH)36·10(H2O) P 2₁/a 2/m

Other Silhydrite Information

References:

NAME( MinRec) 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 Silhydrite Specimen Label here :

Silhydrite

3SiO2·(H2O)
Dana No: 75.2.4.1 Strunz No: VIII/H.39-10
Locality:

Notes: