Trigonite Mineral Data

General Trigonite Information

Chemical Formula:

Pb3Mn(As+++O3)2(As+++O2OH)

Composition:

Molecular Weight = 1,046.31 gm

Manganese 5.25 % Mn 6.78 % MnO

Arsenic 21.48 % As 28.36 % As₂O₃

Hydrogen 0.10 % H 0.86 % H₂O

Lead 59.41 % Pb 64.00 % PbO

Oxygen 13.76 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Pb₃Mn²⁺(AsO₃)₂(AsO₂OH)

Environment:

In a metamorphosed Fe-Mn orebody.

IMA Status:

Valid Species (Pre-IMA) 1920

Locality:

Langban, Varmland, Sweden. Link to MinDat.org Location Data.

Name Origin:

Named from the Greek for triangle, alluding to the characteristic crystal outline

Name Pronunciation:

Trigonite + Pronunciation

Synonym:

ICSD 100410

PDF 23-330

Trigonite Crystallography

Axial Ratios:

a:b:c =1.0661:1:1.6279

Cell Dimensions:

a = 7.25, b = 6.8, c = 11.07, Z = 2; beta = 91.817° V = 545.48 Den(Calc)= 6.37

Crystal System:

Monoclinic - Domatic H-M Symbol (m) Space Group: Pn

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

By Intensity(I/I_o): 2.99(1), 3.08(0.9), 3.24(0.7),

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Forms: ( 1 1 0) ( 0 1 0) ( 1 0 1) ( 1 0 1) ( 1 0 0) ( 0 0 1)

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Physical Properties of Trigonite

Cleavage:

{010} Perfect

Color:

Brown, Yellow, Yellow brown, Sulfur yellow.

Density:

6.1 - 7.1, Average = 6.6

Diaphaneity:

Translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Hardness:

2-3 - Gypsum-Calcite

Luster:

Vitreous - Adamantine

Streak:

yellow

Optical Properties of Trigonite

Gladstone-Dale:

CI meas= 0.011 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.024 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1722,KPDmeas= 0.1662,KC= 0.1681
Ncalc = 2.03 - 2.19

Optical Data:

Biaxial (-), a=2.07, b=2.1, g=2.12, bire=0.0500

Calculated Properties of Trigonite

Electron Density:

Bulk Density (Electron Density)=5.59 gm/cc
note: Specific Gravity of Trigonite =6.60 gm/cc.

Fermion Index:

Fermion Index = 0.13
Boson Index = 0.87

Photoelectric:

PE_Trigonite=1,094.92 barns/electron
U=PE_Trigonite x rElectron Density=6,119.29 barns/cc.

Radioactivity:

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

Trigonite Classification

Dana Class:

45.01.02.01 (45)Acid and normal Antimonites, Arsenites and Phosphites

(45.01)with miscellaneous formulae

(45.01.02)Trigonite Group

45.01.02.01 Trigonite Pb3Mn(AsO3)2(AsO2OH) Pn m

45.01.02.02 Rouseite Pb2Mn(AsO3)2•2(H2O) P1,P 1 Tri

Strunz Class:

04.JB.40 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.J - Arsenites, Antimonites, Bismuthites, Sulfites,

04.JB -Arsenites, antimonites, bismuthites; with additional anions, without H2O

04.JB.40 Trigonite Pb3Mn(AsO3)2(AsO2OH) Pn m

Other Trigonite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Trigonite :
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 Trigonite Specimen Label here :

Trigonite

Pb3Mn(As+++O3)2(As+++O2OH)
Dana No: 45.01.02.01 Strunz No: 04.JB.40
Locality:

Notes:

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