Lewisite Mineral Data

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General Lewisite Information

Chemical Formula:

(Ca,Fe++,Na)2(Sb,Ti)2O7

Composition:

Molecular Weight = 426.94 gm

Sodium 0.81 % Na 1.09 % Na₂O

Calcium 12.20 % Ca 17.08 % CaO

Titanium 2.24 % Ti 3.74 % TiO₂

Manganese 0.64 % Mn 0.83 % MnO

Iron 6.54 % Fe 8.41 % FeO

Antimony 51.33 % Sb 68.19 % Sb₂O₅

Oxygen 26.23 % O

______ ______

100.00 % 99.34 % = TOTAL OXIDE

Empirical Formula:

Ca_1.3Fe²⁺_0.5Na_0.15Mn²⁺_0.05Sb_1.8Ti_0.2O₇

Environment:

An alteration of large tetrahedrite crystals and in eluvial sands. Lewisite (1899) is now considered Ti-bearing romeite.

IMA Status:

Discredited IMA 2006 (Dana # Added)

Locality:

Tripuhy cinnabar mine, Ouro Preto, Minas Gerais, Barzil. Link to MinDat.org Location Data.

Name Origin:

Named for Willam James Lewis (1847-1926), Professor of Mineralogy, Cambridge University, Canbridge, England.

Name Pronunciation:

Lewisite

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Lewisite Crystallography

Cell Dimensions:

a = 10.64, Z = 8; V = 1,204.55 Den(Calc)= 4.71

Crystal System:

Isometric - HexoctahedralH-M Symbol (4/m 3 2/m) Space Group: F d3m

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

By Intensity(I/I_o): 1.548(1), 1.813(1), 2.94(1),0.989(0.5), 1.05(0.5), 1.15(0.5), 1.179(0.5),

Crystal Structure:

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Rouse R C , Dunn P J , Peacor D R , Wang L , Journal of Solid State Chemistry , 141 (1998) p.562-569, Structural studies of the natural antimonian pyrochlores I. Mixed valency,, cation site splitting, and symmetry reduction in lewisite, Locality: cinnabar mine, Tripuhy, Ouro Preto, Minas Gerias, Brazil, Sample: F23 refinement

Physical Properties of Lewisite

Cleavage:

{111} Imperfect, {111} Imperfect, {111} Imperfect

Color:

Honey yellow, Amber yellow, Yellowish brown.

Density:

4.95

Diaphaneity:

Transparent to Subopaque

Fracture:

Hackly - Jagged, torn surfaces, (e.g. fractured metals).

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Pulverulent - Forms a loose, poorly-coherent powdery mass.

Hardness:

5.5 - Knife Blade

Luster:

Vitreous - Resinous

Streak:

light yellowish brown

Optical Properties of Lewisite

Optical Data:

Isotropic.

NCalc= 1.82 - from Gladstone-Dale relationship (KC = 0.1744) where Ncalc=Dcalc*KC+1
NCalc= 1.86 - from Gladstone-Dale relationship (KC = 0.1744) where Ncalc=Dmeas*KC+1

Calculated Properties of Lewisite

Electron Density:

Bulk Density (Electron Density)=4.28 gm/cc
note: Specific Gravity of Lewisite =4.71 gm/cc.

Fermion Index:

Fermion Index = 0.0045773186
Boson Index = 0.9954226814

Photoelectric:

PE_Lewisite= 170.36 barns/electron
U=PE_Lewisite x rElectron Density= 729.57 barns/cc.

Radioactivity:

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

Lewisite Classification

Dana Class:

44.01.01.03a (44)Antimonates

(44.01)(A)2 (X2 O6) (O,OH,F)

(44.01.01)Stibiconite Group

44.01.01.01 Stibiconite SbSb2O6(OH) F d3m 4/m 3 2/m

44.01.01.02 Bindheimite Pb2Sb2O6(O,OH) F d3m 4/m 3 2/m

44.01.01.03 Romeite (Ca,Fe,Mn,Na)2(Sb,Ti)2O6(O,OH,F) F d3m 4/m 3 2/m

44.01.01.03a Lewisite? (Ca,Fe,Na)2(Sb,Ti)2O7 F d3m 4/m 3 2/m

44.01.01.04 Monimolite (Pb,Ca)2Sb2O7 F d3m 4/m 3 2/m

44.01.01.05 Stetefeldtite Ag2Sb2O6(O,OH) F d3m 4/m 3 2/m

44.01.01.06 Bismutostibiconite Bi(Sb,Fe)2O7 F d3m 4/m 3 2/m

44.01.01.07 Partzite Cu2Sb2(O,OH)7(?) F d3m 4/m 3 2/m

Strunz Class:

08.XX.00 08 - PHOSPHATES, ARSENATES, VANADATES

08.X - Unclassified Strunz PHOSPHATES, ARSENATES, VANADATES

08.XX -Stibiconite Group

08.XX.00 Arsenobismite? Bi2(AsO4)(OH)3 Unk Ortho

08.XX.00 Coeruleolactite (Ca,Cu)Al6(PO4)4(OH)8•4-5(H2O) P1 1

08.XX.00 Cheralite-(Ce)? (Ce,Ca,Th)(P,Si)O4 P 2₁/n 2/m

08.XX.00 Chernovite-(Ce)* (Ce,Y)(AsO4) I 4₁/amd 4/m 2/m 2/m

08.XX.00 Kerstenite? PbSeO4(?) P nma 2/m 2/m 2/m

08.XX.00 Laubmannite? Fe3Fe6(PO4)4(OH)12 Unk Ortho

08.XX.00 Spodiosite? Ca2(PO4)F Pbcm 2/m 2/m 2/m

08.XX.00 Pseudo-autunite* (H3O)4Ca2(UO2)2(PO4)4•5(H2O)(?) Unk Ortho

08.XX.00 Viseite Ca10Al24(SiO4)6(PO4)7O22F3•72(H2O)(?) I a3d 4/m 3 2/m

08.XX.00 Vanuranylite? (H3O,Ba,Ca,K)1.6(UO2)2V2O8•4(H2O)(?) C 2/c ? 2/m

08.XX.00 Sodium-autunite Na2(UO2)2(PO4)2•8(H2O) P 4/nmm 4/m 2/m 2/m

08.XX.00 Sodium meta-autunite! Na2(UO2)2(PO4)2•6-8(H2O) P 4/nmm 4/m 2/m 2/m

08.XX.00 Slavkovite! Cu13(AsO4)6(AsO3OH)4•23(H2O) P1 1

08.XX.00 IMA2000-020! Fe4[AsO3OH]5[AsO2(OH)2]2•20(H2O) Ortho Ortho

08.XX.00 Lewisite! (Ca,Fe,Na)2(Sb,Ti)2O7 F d3m 4/m 3 2/m

08.XX.00 Kamarizaite! Fe3(AsO4)2(OH)3•3H2O Pccm, Pcc2, Pcmm, Pcm21 Ortho

08.XX.00 Lapeyreite! Cu3O[AsO3(OH)]2•H2O C 2/m 2/m

08.XX.00 IMA2008-063 Pb[Zn0.25,[]0.75]Fe3H(AsO4)2(OH)6 C 2/c 2/m

08.XX.00 IMA2009-002! Cu3(AsO4)2 P 2₁/c 2/m

08.XX.00 IMA2009-005 (Y,Ca,REE)5[(Si,P)O4]3F P 6₃/m 6/m 2/m 2/m

08.XX.00 IMA2009-016 Cu4H(AsO4)2(OH)3•H2O P1 1

Other Lewisite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(AntBidBlaNic3) OPTIC PROP.(AntBidBlaNic3)

See Also:

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

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

Lewisite

(Ca,Fe++,Na)2(Sb,Ti)2O7
Dana No: 44.01.01.03a Strunz No: 08.XX.00
Locality:

Notes: