Segnitite Mineral Data

General Segnitite Information

Chemical Formula:

PbFe+++3H(AsO4)2(OH)6

Composition:

Molecular Weight = 755.63 gm

Iron 22.17 % Fe 31.70 % Fe₂O₃

Arsenic 19.83 % As 30.42 % As₂O₅

Hydrogen 0.93 % H 8.34 % H₂O

Lead 27.42 % Pb 29.54 % PbO

Oxygen 29.64 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

PbFe³⁺₃H(AsO₄)₂(OH)₆

Environment:

Oxidized zone of a Pb-Zn orebody.

IMA Status:

Approved IMA 1992

Locality:

Broken Hill, New South Wales, and at Coppin Pool, about 41 km east-southeast of Mt. Tom Price, Western Australia. Link to MinDat.org Location Data.

Name Origin:

Named for E. Ralph Segnit (1923-1999), mineralogist and petrologist, University of Adelaide, Adelaide, Australia, for his contributions to Australian mineralogy.

Synonym:

ICSD 40681

IMA1991-017

PDF 45-1392

Segnitite Image

Images:

Segnitite

Comments: Translucent yellow crystalline segnitite crust.
Location: Kintore Open Cut, Broken Hill, New South Wales, Australia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Segnitite Crystallography

Axial Ratios:

a:c = 1:2.32545

Cell Dimensions:

a = 7.359, c = 17.113, Z = 3; V = 802.59 Den(Calc)= 4.69

Crystal System:

Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3m

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

By Intensity(I/I_o): 3.092(1), 5.966(0.5), 3.678(0.4),

Physical Properties of Segnitite

Cleavage:

{???} Good

Color:

Greenish brown, Yellow brown.

Diaphaneity:

Transparent to Translucent

Hardness:

4 - Fluorite

Luster:

Adamantine

Streak:

light yellow

Optical Properties of Segnitite

Gladstone-Dale:

CI calc= 0.051 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2058,KC= 0.2168
Ncalc = 2.02

Optical Data:

Uniaxial (-), e=1.955, w=1.975, bire=0.0200.

Calculated Properties of Segnitite

Electron Density:

Bulk Density (Electron Density)=4.28 gm/cc
note: Specific Gravity of Segnitite =4.69 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_Segnitite= 482.13 barns/electron
U=PE_Segnitite x rElectron Density=2,064.79 barns/cc.

Radioactivity:

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

Segnitite Classification

Dana Class:

42.07.04.04 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.07)where (AB)5 (XO4)3 Zq ï¿½ x(H2O)

(42.07.04)Arsenocrandallite Group

42.07.04.01 Arsenocrandallite (Ca,Sr)Al3[(As,P)O4]2(OH)5•(H2O) R 3m 3m

42.07.04.02 Philipsbornite PbAl3(AsO4)2(OH)5•(H2O) R 3m-,R 3m Trig

42.07.04.03 Arsenogoyazite (Sr,Ca,Ba)Al3(AsO4,PO4)2(OH,F)5•(H2O) R 3m 3 2/m

42.07.04.04 Segnitite PbFe3H(AsO4)2(OH)6 R 3m 3 2/m

Strunz Class:

08.BL.10 08 - PHOSPHATES, ARSENATES, VANADATES

08.B - Phosphates, etc. with Additional Anions, without H2O

08.BL -With medium-sized and large cations, (OH, etc.):RO4 = 3:1

08.BL.10 Arsenogorceixite! BaAl3AsO3(OH)(AsO4,PO4)(OH,F)6 R 3m 3 2/m

08.BL.10 Arsenocrandallite (Ca,Sr)Al3[(As,P)O4]2(OH)5•(H2O) R 3m 3m

08.BL.10 Ferrazite? (Pb,Ba)3(PO4)2•8(H2O)(?) Tri

08.BL.10 Arsenowaylandite* BiAl3(AsO4)2(OH)6 R 3m 3 2/m

08.BL.10 Benauite! HSrFe3(PO4)2(OH)6 R 3m 3 2/m

08.BL.10 Arsenogoyazite (Sr,Ca,Ba)Al3(AsO4,PO4)2(OH,F)5•(H2O) R 3m 3 2/m

08.BL.10 Dussertite BaFe3(AsO4)2(OH)5 R 3m 3m

08.BL.10 Crandallite CaAl3(PO4)2(OH)5•(H2O) R 3m 3 2/m

08.BL.10 Goyazite SrAl3(PO4)2(OH)5•(H2O) R 3m 3 2/m

08.BL.10 Gorceixite BaAl3(PO4)(PO3OH)(OH)6 R 3m 3 2/m

08.BL.10 Kintoreite PbFe3(PO4)2(OH,H2O)6 R 3m 3 2/m

08.BL.10 Lusungite? (Sr,Pb)Fe3(PO4)2(OH)5•(H2O) R 3m 3m

08.BL.10 Philipsbornite PbAl3(AsO4)2(OH)5•(H2O) R 3m-,R 3m Trig

08.BL.10 Plumbogummite PbAl3(PO4)2(OH)5•(H2O) R 3m 3 2/m

08.BL.10 Segnitite PbFe3H(AsO4)2(OH)6 R 3m 3 2/m

08.BL.10 Springcreekite! BaV3(PO4)2(OH,H2O)6 R 3m 3 2/m

Other Segnitite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Am.Min.,Vol.77,p656-659,1992) OPTIC PROP.(Am.Min.,Vol.77,p656-659,1992)

See Also:

Links to other databases for Segnitite :
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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Segnitite

PbFe+++3H(AsO4)2(OH)6
Dana No: 42.07.04.04 Strunz No: 08.BL.10
Locality:

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