Lewisite Mineral Data

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.

IMA Status:

Valid Species (Pre-IMA) 1899 (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.

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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

Physical Properties of Lewisite

Cleavage:

[111] Imperfect, [111] Imperfect, [111] Imperfect

Color:

Honey yellow, Amber yellow, Yellowish brown.

Density:

4.95

Diaphaniety:

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:

r_electron=4.28 gm/cc
note: r_Lewisite=4.71 gm/cc.

Fermion Index

Fermion Index = 0.00457
Boson Index = 0.99543

Photoelectric:

PE_Lewisite= 170.36 barns/electron
U=PE_Lewisite x r_electron= 729.57 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Lewisite is Not Radioactive

Lewisite Classification

Dana Class:

44.1.1.3a (44)Antimonates

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

(44.1.1)Dana Group

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

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

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

44.1.1.3a Lewisite ! (Ca,Fe,Na)2(Sb,Ti)2O7 F d3m 4/m 3 2/m

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

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

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

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

Strunz Class:

IV/C.11-30 IV - Oxides

IV/C - Oxides with metal : oxygen = 2:3 (M2O3 and related compounds)

IV/C.11 - Stibiconite group, Partzite - Bindheimite series

IV/C.11-10 Partzite Cu2Sb2(O,OH)7(?) F d3m 4/m 3 2/m

IV/C.11-20 Stetefeldtite Ag2Sb2O6(O,OH) F d3m 4/m 3 2/m

IV/C.11-30 Lewisite (Ca,Fe,Na)2(Sb,Ti)2O7 F d3m 4/m 3 2/m

IV/C.11-40 Romeite (Ca,Fe,Mn,Na)2(Sb,Ti)2O6(O,OH,F) F d3m 4/m 3 2/m

IV/C.11-50 Stibiconite SbSb2O6(OH) F d3m 4/m 3 2/m

IV/C.11-60 Bismutostibiconite Bi(Sb,Fe)2O7 F d3m 4/m 3 2/m

IV/C.11-70 Bindheimite Pb2Sb2O6(O,OH) F d3m 4/m 3 2/m

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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Lewisite

(Ca,Fe++,Na)2(Sb,Ti)2O7
Dana No: 44.1.1.3a Strunz No: IV/C.11-30
Locality:

Notes: