Stokesite Mineral Data

Stokesite Mineral Data +

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General Stokesite Information

Chemical Formula:

CaSnSi3O9·2(H2O)

Composition:

Molecular Weight = 423.07 gm

Calcium 9.47 % Ca 13.25 % CaO

Silicon 19.92 % Si 42.61 % SiO₂

Tin 28.06 % Sn 31.84 % SnO

Hydrogen 0.95 % H 8.52 % H₂O

Oxygen 41.60 % O

______ ______

100.00 % 96.22 % = TOTAL OXIDE

Empirical Formula:

CaSnSi₃O₉·2(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1899

Locality:

Roscommon Cliff, St. Just, Cornwall, England. Link to MinDat.org Location Data.

Synonym:

ICSD 34348

PDF 13-109

Stokesite Image

Images:

Stokesite

Comments: Colorless transparent stokesite microcrystal in albite.
Location: Corrego do Urucum, Galileia, Minas Gerais, Brazil. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Stokesite

Comments: Thick, tabular crystals of stokesite, perched atop a 2 cm sphere of feldspar crystals.
Location: Corrego do Urucum, near Galilea, Minas Gerais, Brazil. Scale: 3.3 x 2.5 x 2 cm.
© Rob Lavinsky

Images:

Stokesite Stannomicrolite

Comments: Stokesite "ball" composed of lath-like tan or clear crystals with several micro crystals of yellow stannomicrolite.
Location: Urucum mine, Galileia, Minas Gerais, Brazil. Scale: 1.2 cm.
© Tom Loomis / Dakota Matrix

Stokesite Crystallography

Axial Ratios:

a:b:c =1.2411:1:0.4504

Cell Dimensions:

a = 14.41, b = 11.61, c = 5.23, Z = 4; V = 874.98 Den(Calc)= 3.21

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pnna

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

By Intensity(I/I_o): 2.89(1), 3.99(1), 7.25(0.8),

Crystal Structure:

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Vorma A , Mineralogical Magazine , 33 (1963) p.615-617, Crystal structure of stokesite, CaSnSi3O9*2H2O

Physical Properties of Stokesite

Cleavage:

[???] Good, [???] Good

Color:

Colorless.

Density:

3.2

Diaphaniety:

Transparent to translucent

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Stokesite

Gladstone-Dale:

CI meas= -0.009 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1912,KPDmeas= 0.1918,KC= 0.19

Optical Data:

Biaxial (+), a=1.609, b=1.613, g=1.619, bire=0.0100, 2V(Calc)=80, 2V(Meas)=69.5.

Calculated Properties of Stokesite

Electron Density:

r_electron=3.10 gm/cc
note: r_Stokesite=3.21 gm/cc.

Fermion Index

Fermion Index = 0.05626
Boson Index = 0.94374

Photoelectric:

PE_Stokesite= 82.15 barns/electron
U=PE_Stokesite x r_electron= 254.32 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Stokesite is Not Radioactive

Stokesite Classification

Dana Class:

65.5.1.1 (65)Inosilicate Single-Width Unbranched Chains, W=1

(65.5)with chains P=6

(65.5.1)Dana Group

65.5.1.1 Stokesite CaSnSi3O9·2(H2O) Pnna 2/m 2/m 2/m

Strunz Class:

VIII/F.29-30 VIII - Silicates

VIII/F - Inosilicates (chain and band) Six chains [Si6O18]12- and six bands [Si12O30]12-

VIII/F.29 - Hilairite - Stokesite series

VIII/F.29-10 Hilairite Na2ZrSi3O9·3(H2O) R 3m 3 2/m

VIII/F.29-20 Calciohilairite CaZrSi3O9·3(H2O) R 32 3 2

VIII/F.29-24 Pyatenkoite-(Y)! Na5(Y,Dy,Gd)TiSi6O18·6(H2O) R 32 3 2

VIII/F.29-25 Sazykinaite-(Y) Na5YZrSi6018·6(H2O) R 32 3 2

VIII/F.29-30 Stokesite CaSnSi3O9·2(H2O) Pnna 2/m 2/m 2/m

Other Stokesite Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

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

Stokesite

CaSnSi3O9·2(H2O)
Dana No: 65.5.1.1 Strunz No: VIII/F.29-30
Locality:

Notes: