Hornesite Mineral Data
General Hornesite Information
Chemical Formula:
Mg3(AsO4)2•8(H2O)
Composition:
Molecular Weight = 494.88 gm
Magnesium 14.73 % Mg 24.43 % MgO
Arsenic 30.28 % As 46.44 % As2 O5
Hydrogen 3.26 % H 29.12 % H2 O
Oxygen 51.73 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Mg3 (AsO4 )2 •8(H2 O)
Environment:
Lmestone blocks, thermally metamorphosed, in a volcanic tuff (Fiano, Italy).
IMA Status:
Valid Species (Pre-IMA) 1860
Locality:
Banat, Hungary [probably Oravi�ta or Csiklova, Romania]. Link to MinDat.org Location Data.
Name Origin:
Named for Moritz Hornes (1815-1868), Curator of the Imperial Cabinet, Vienna, Austria.
Name Pronunciation:
Hornesite + Pronunciation
Synonym:
Hoernesite
Hornesite Image
Images:
Hornesite Crystallography
Axial Ratios:
a:b:c =0.7633:1:0.3526
Cell Dimensions:
a = 10.26, b = 13.44, c = 4.74, Z = 2; beta = 104.9° V = 631.64 Den(Calc)= 2.60
Crystal System:
Monoclinic - Prismatic H-M Symbol (2/m) Space Group: I2/m
X Ray Diffraction:
By Intensity(I/Io ): 6.692(1), 2.712(0.5), 3.005(0.5),
Physical Properties of Hornesite
Color:
White.
Density:
2.57
Diaphaneity:
Transparent
Hardness:
1 - Talc
Luster:
Pearly
Optical Properties of Hornesite
Gladstone-Dale:
CI meas = -0.006 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = 0.006 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2218,KPDmeas = 0.2244,KC = 0.2231 Ncalc = 1.57 - 1.58
Optical Data:
Biaxial (+), a=1.563, b=1.571, g=1.596, bire=0.0330, 2V(Calc)=60, 2V(Meas)=60.
Calculated Properties of Hornesite
Electron Density:
Bulk Density (Electron Density)=2.58 gm/cc note: Specific Gravity of Hornesite =2.60 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PEHornesite = 20.16 barns/electronU=PEHornesite x r Electron Density= 52.10 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Hornesite is Not Radioactive
Hornesite Classification
Dana Class:
40.03.06.07 (40) Hydrated Phosphates, etc
(40.03) where (A++)3 (XO4)2 � x(H2O)
(40.03.06) Vivianite Group
40.03.06.01 Vivianite Fe3(PO4)2•8(H2O) C 2/m 2/m
40.03.06.02 Baricite (Mg,Fe)3(PO4)2•8(H2O) C 2/m 2/m
40.03.06.03 Erythrite Co3(AsO4)2•8(H2O) I2/m 2/m
40.03.06.04 Annabergite Ni3(AsO4)2•8(H2O) I2/m 2/m
40.03.06.05 Kottigite Zn3(AsO4)2•8(H2O) C 2/m 2/m
40.03.06.06 Parasymplesite Fe3(AsO4)2•8(H2O) C 2/m 2/m
40.03.06.07 Hornesite Mg3(AsO4)2•8(H2O) I2/m 2/m
40.03.06.08 Arupite (Ni,Fe)3(PO4)2•8(H2O) I2/m 2/m
40.03.06.09 Pakhomovskyite ! Co3(PO4)2•8(H2O) C 2/m 2/m
Strunz Class:
08.CE.40 08 - PHOSPHATES, ARSENATES, VANADATES
08.C - Phosphates without Additional Anions, with H2O
08.CE -With only medium-sized cations, RO4:H2O � 1:2.5
08.CE.40 Arupite (Ni,Fe)3(PO4)2•8(H2O) I2/m 2/m
08.CE.40 Annabergite Ni3(AsO4)2•8(H2O) I2/m 2/m
08.CE.40 Baricite (Mg,Fe)3(PO4)2•8(H2O) C 2/m 2/m
08.CE.40 Erythrite Co3(AsO4)2•8(H2O) I2/m 2/m
08.CE.40 Ferrisymplesite Fe3(AsO4)2(OH)3•5(H2O) None
08.CE.40 Hornesite Mg3(AsO4)2•8(H2O) I2/m 2/m
08.CE.40 Kottigite Zn3(AsO4)2•8(H2O) C 2/m 2/m
08.CE.40 Manganohornesite (Mn,Mg)3(AsO4)2•8(H2O) P 21 /c 2/m
08.CE.40 Parasymplesite Fe3(AsO4)2•8(H2O) C 2/m 2/m
08.CE.40 Vivianite Fe3(PO4)2•8(H2O) C 2/m 2/m
08.CE.40 Pakhomovskyite ! Co3(PO4)2•8(H2O) C 2/m 2/m
Other Hornesite 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 Hornesite :
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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Hornesite
Mg3(AsO4)2•8(H2O)
Dana No: 40.03.06.07 Strunz No: 08.CE.40
Locality:
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