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 % As₂O₅

Hydrogen 3.26 % H 29.12 % H₂O

Oxygen 51.73 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₃(AsO₄)₂•8(H₂O)

Environment:

Lmestone blocks, thermally metamorphosed, in a volcanic tuff (Fiano, Italy).

IMA Status:

Valid Species (Pre-IMA) 1860

Locality:

Banat, Hungary [probably Oraviï¿½ta 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

Comments: Aggregate of white pearly platy crystals of hornesite on matrix.
Location: Bauhaus, Richelsdorf, Hessen, Germany. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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

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

By Intensity(I/I_o): 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:

PE_Hornesite= 20.16 barns/electron
U=PE_Hornesite x rElectron 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 ï¿½ 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 ï¿½ 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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Print or Cut-and-Paste your Hornesite Specimen Label here :

Hornesite

Mg3(AsO4)2•8(H2O)
Dana No: 40.03.06.07 Strunz No: 08.CE.40
Locality:

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