Launayite Mineral Data

Launayite Mineral Data +

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General Launayite Information

Chemical Formula:

Pb22Sb26S61

Composition:

Molecular Weight = 9,679.93 gm

Antimony 32.70 % Sb

Lead 47.09 % Pb

Sulfur 20.21 % S

______

100.00 %

Empirical Formula:

Pb₂₂Sb₂₆S₆₁

Environment:

Hydrothermal vein mineral in marble.

IMA Status:

Approved IMA 1967

Locality:

Madoc, Ontario, Canada. Link to MinDat.org Location Data.

Name Origin:

Named for Louis de Launay (1860-1938), French student of mineral deposits.

Synonym:

IMA1966-021

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Launayite Crystallography

Axial Ratios:

a:b:c =10.6052:1:8.0099

Cell Dimensions:

a = 42.58, b = 4.015, c = 32.16, Z = 2; beta = 102.017° V = 5,377.55 Den(Calc)= 5.98

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

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

By Intensity(I/I_o): 3.45(1), 2.92(0.8), 4.17(0.8),

Physical Properties of Launayite

Cleavage:

[100] Perfect, [001] Perfect

Color:

Lead gray.

Density:

5.75

Diaphaniety:

Opaque

Hardness:

3.5-4 - Copper Penny-Fluorite

Luster:

Metallic

Streak:

black

Optical Properties of Launayite

RL Anisotrophism:

Strong.

RL Pleochroism:

Fairly strong, from white to gray.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Launayite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	42.60	38.60
546 nm	43.80	36.90
589 nm	42.70	36.20
650 nm	40.90	35.50

**Calculated Relative Intensity Colors of Launayite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%	250%
R₁
R₂

Calculated Properties of Launayite

Electron Density:

r_electron=5.07 gm/cc
note: r_Launayite=5.98 gm/cc.

Fermion Index

Fermion Index = 0.10558
Boson Index = 0.89442

Photoelectric:

PE_Launayite= 966.70 barns/electron
U=PE_Launayite x r_electron=4,904.22 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Launayite is Not Radioactive

Launayite Classification

Dana Class:

3.6.6.1 (3)Sulfides - Sulfosalts

(3.6)where 2 < z/y < 2.49 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(3.6.6)Dana Group

3.6.6.1 Launayite Pb22Sb26S61 C 2/m 2/m

Strunz Class:

II/E.20-20 II - Sulfides and sulphosalts

II/E - Sulfosalts (S : As,Sb,Bi = x), Sulfosalts with predominant Iron and Copper x = 2.0

II/E.20 - Madocite - Dadsonite series

II/E.20-10 Madocite Pb17(Sb,As)16S41 Pb2a mm2

II/E.20-20 Launayite Pb22Sb26S61 C 2/m 2/m

II/E.20-25 Pellouxite! (Cu,Ag)Pb10Sb12S27(Cl,S)0.6O C 2/m 2/m

II/E.20-30 Sterryite Ag2Pb10(Sb,As)12S29 Pbam 2/m 2/m 2/m

II/E.20-40 Playfairite Pb16Sb18S43 P 2₁/m 2/m

II/E.20-50 Sorbyite Pb19(Sb,As)20S49 C 2/m 2/m

II/E.20-60 Dadsonite Pb21Sb23S55Cl P 2,Pm,P 2/m Mono

Other Launayite Information

References:

NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

See Also:

Links to other databases for Launayite :
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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Print or Cut-and-Paste your Launayite Specimen Label here :

Launayite

Pb22Sb26S61
Dana No: 3.6.6.1 Strunz No: II/E.20-20
Locality:

Notes: