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 % Fe2 O3
Arsenic 19.83 % As 30.42 % As2 O5
Hydrogen 0.93 % H 8.34 % H2 O
Lead 27.42 % Pb 29.54 % PbO
Oxygen 29.64 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
PbFe3+ 3 H(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 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 3 m
X Ray Diffraction:
By Intensity(I/Io ): 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:
PESegnitite = 482.13 barns/electronU=PESegnitite x r Electron 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 � 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 3 m 3 2/m
42.07.04.04 Segnitite PbFe3H(AsO4)2(OH)6 R 3 m 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 3 m 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 3 m 3 2/m
08.BL.10 Benauite ! HSrFe3(PO4)2(OH)6 R 3 m 3 2/m
08.BL.10 Arsenogoyazite (Sr,Ca,Ba)Al3(AsO4,PO4)2(OH,F)5•(H2O) R 3 m 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 3 m 3 2/m
08.BL.10 Goyazite SrAl3(PO4)2(OH)5•(H2O) R 3 m 3 2/m
08.BL.10 Gorceixite BaAl3(PO4)(PO3OH)(OH)6 R 3 m 3 2/m
08.BL.10 Kintoreite PbFe3(PO4)2(OH,H2O)6 R 3 m 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 3 m 3 2/m
08.BL.10 Segnitite PbFe3H(AsO4)2(OH)6 R 3 m 3 2/m
08.BL.10 Springcreekite ! BaV3(PO4)2(OH,H2O)6 R 3 m 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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