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Hörnesite
A valid IMA mineral species - grandfathered
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About Hörnesite
Moriz Hoernes
Formula:
Mg3(AsO4)2 · 8H2O
Colour:
White; colorless in transmitted light
Lustre:
Sub-Vitreous, Silky, Pearly
Hardness:
1
Specific Gravity:
2.57 - 2.73
Crystal System:
Monoclinic
Member of:
Name:
Named by Wilhelm Haidinger in 1860 in honor of Moriz Hörnes, the elder (14 July 1815, Vienna, Austrian Empire - 4 November 1868, Vienna, Austrian Empire), Curator of the Imperial Mineral Cabinet, Vienna, Austria.
Vivianite Group. Erythrite-Hörnesite Series.
Forms solid solution series mainly with annabergite and erythrite.
In 2024 a Mg-dominant Mg/Ni-ordered intermediate member of the solid-solution series between annabergite and hörnesite was named cabrerite (not to be confused with "Cabrerite (of Dana)", a Mg-bearing variety of annabergite).
Forms solid solution series mainly with annabergite and erythrite.
In 2024 a Mg-dominant Mg/Ni-ordered intermediate member of the solid-solution series between annabergite and hörnesite was named cabrerite (not to be confused with "Cabrerite (of Dana)", a Mg-bearing variety of annabergite).
Name Encoding
ASCII-7:
Hornesite
Unique Identifiers
Mindat ID:
1931
Long-form identifier:
mindat:1:1:1931:2
IMA Classification of Hörnesite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Mg3(As5+O4)2·8H2O
First published:
1860
Classification of Hörnesite
8.CE.40
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
40.3.6.7
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
3 : A3(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
3 : A3(XO4)2·xH2O
20.2.4
20 : Arsenates (also arsenates with phosphate, but without other anions)
2 : Arsenates of Be, Mg, Ca or Ba
20 : Arsenates (also arsenates with phosphate, but without other anions)
2 : Arsenates of Be, Mg, Ca or Ba
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Hns | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Hns | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Hörnesite
Sub-Vitreous, Silky, Pearly
Transparency:
Transparent
Comment:
Luster is pearly on cleavages.
Colour:
White; colorless in transmitted light
Streak:
White to colorless
Hardness:
1 on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
On {010}, perfect; on {100}, poor.
On {010}, perfect; on {100}, poor.
Density:
2.57 - 2.73 g/cm3 (Measured) 2.57 g/cm3 (Calculated)
Comment:
Density measured on artificial material = 2.609.
Optical Data of Hörnesite
Type:
Biaxial (+)
RI values:
nα = 1.563 nβ = 1.571 nγ = 1.596
2V:
Measured: 60° , Calculated: 60°
Birefringence:
0.033
Max. Birefringence:
δ = 0.033
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
strong
Optical Extinction:
X=b, Z^c = 31°
Pleochroism:
Non-pleochroic
Chemistry of Hörnesite
Mindat Formula:
Mg3(AsO4)2 · 8H2O
Element Weights:
Elements listed:
Crystallography of Hörnesite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 10.262 Å, b = 13.442 Å, c = 4.741 Å
β = 104.9°
β = 104.9°
Ratio:
a:b:c = 0.763 : 1 : 0.353
Unit Cell V:
631.99 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals prismatic [001] and flattened {010}. Also occurs with a columnar structure; radial-foliated.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.692 Å | (100) |
| 3.217 Å | (30) |
| 3.005 Å | (50) |
| 2.779 Å | (30) |
| 2.734 Å | (30) |
| 2.712 Å | (50) |
| 1.692 Å | (25) |
Comments:
Also ICDD 35-856 (synthetic)
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations |
Geological Setting:
Oxidized arsenic ore deposits.
On fractures in serpentine.
In marble xenoliths.
Post-mine efflorescence on tunnel walls or dump rocks.
On fractures in serpentine.
In marble xenoliths.
Post-mine efflorescence on tunnel walls or dump rocks.
Type Occurrence of Hörnesite
Place of Conservation of Type Material:
Natural History Museum, Vienna, Austria, A.a. 415.
Geological Setting of Type Material:
Oxidized copper-molybdenum deposit.
Associated Minerals at Type Locality:
Synonyms of Hörnesite
Other Language Names for Hörnesite
Relationship of Hörnesite to other Species
Member of:
Other Members of Vivianite Group:
| Annabergite | Ni3(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Arupite | Ni3(PO4)2 · 8H2O | Mon. 2/m : B2/m |
| Babánekite | Cu3(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Barićite | (Mg,Fe)3(PO4)2 · 8H2O | Mon. 2/m : B2/m |
| Cabrerite | NiMg2(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Erythrite | Co3(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Gritsenkoite | CoMg2(AsO4)2(H2O)8 | Mon. 2/m : B2/m |
| Köttigite | Zn3(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Manganohörnesite | Mn2+3(AsO4)2 · 8H2O | Mon. 2/m : P2/c |
| Monteneroite | Cu2+Mn2+2(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Pakhomovskyite | Co3(PO4)2 · 8H2O | Mon. 2/m : B2/m |
| Parasymplesite | Fe2+3(AsO4)2 · 8H2O | Mon. 2/m : B2/m |
| Vivianite | Fe2+Fe2+2(PO4)2 · 8H2O | Mon. 2/m : B2/m |
| Zincocabrerite | ZnMg2(AsO4)2(H2O)8 | Mon. 2/m : B2/m |
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 7 photos of Hörnesite associated with Dolomite | CaMg(CO3)2 |
| 7 photos of Hörnesite associated with Sainfeldite | Ca5(AsO4)2(AsO3OH)2 · 4H2O |
| 6 photos of Hörnesite associated with Hydromagnesite | Mg5(CO3)4(OH)2 · 4H2O |
| 6 photos of Hörnesite associated with Quartz | SiO2 |
| 6 photos of Hörnesite associated with Vladimirite | Ca4(AsO4)2(AsO3OH) · 4H2O |
| 4 photos of Hörnesite associated with Annabergite | Ni3(AsO4)2 · 8H2O |
| 4 photos of Hörnesite associated with Gersdorffite | NiAsS |
| 4 photos of Hörnesite associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
| 4 photos of Hörnesite associated with Realgar | As4S4 |
| 3 photos of Hörnesite associated with Picropharmacolite | Ca4Mg(AsO4)2(HAsO4)2 · 11H2O |
Related Minerals - Strunz-mindat Grouping
| 8.CE. | Monteneroite | Cu2+Mn2+2(AsO4)2 · 8H2O |
| 8.CE. | Belmonteite | CaMn2(AsO4)2 · 7H2O |
| 8.CE. | Zincocabrerite | ZnMg2(AsO4)2(H2O)8 |
| 8.CE.X | Babánekite | Cu3(AsO4)2 · 8H2O |
| 8.CE.05 | Chudobaite | Mg5(AsO4)2(AsO3OH)2 · 10H2O |
| 8.CE.05 | Geigerite | Mn2+5(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.10 | Newberyite | Mg(PO3OH) · 3H2O |
| 8.CE.10 | Manganonewberyite | Mn(PO3OH)(H2O)3 |
| 8.CE.15 | Fanguangite | (MoO2)(PO3OH) · 4H2O |
| 8.CE.15 | Brassite | Mg(HAsO4) · 4H2O |
| 8.CE.20 | Phosphorrösslerite | Mg(PO3OH) · 7H2O |
| 8.CE.20 | Rösslerite | Mg(HAsO4) · 7H2O |
| 8.CE.25 | Switzerite | Mn2+3(PO4)2 · 7H2O |
| 8.CE.25 | Metaswitzerite | Mn2+3(PO4)2 · 4H2O |
| 8.CE.30 | Pradetite | CoCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Veselovskýite | ZnCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Lindackerite | CuCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Klajite | MnCu4(AsO4)2(HAsO4)2 · 9-10H2O |
| 8.CE.30 | Hloušekite | (Ni,Co)Cu4(AsO4)2(AsO3OH)2 · 9H2O |
| 8.CE.30 | Ondrušite | CaCu4(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.35 | Bobierrite | Mg3(PO4)2 · 8H2O |
| 8.CE.40 | Barićite | (Mg,Fe)3(PO4)2 · 8H2O |
| 8.CE.40 | Parasymplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Gritsenkoite | CoMg2(AsO4)2(H2O)8 |
| 8.CE.40 | Cabrerite | NiMg2(AsO4)2 · 8H2O |
| 8.CE.40 | Pakhomovskyite | Co3(PO4)2 · 8H2O |
| 8.CE.40 | Vivianite | Fe2+Fe2+2(PO4)2 · 8H2O |
| 8.CE.40 | Arupite | Ni3(PO4)2 · 8H2O |
| 8.CE.40 | Erythrite | Co3(AsO4)2 · 8H2O |
| 8.CE.40 | Manganohörnesite | Mn2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Köttigite | Zn3(AsO4)2 · 8H2O |
| 8.CE.40 | Ferrisymplesite | Fe3+3(AsO4)2(OH)3 · 5H2O |
| 8.CE.40 | Annabergite | Ni3(AsO4)2 · 8H2O |
| 8.CE.45 | Symplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.50 | Cattiite | Mg3(PO4)2 · 22H2O |
| 8.CE.55 | Koninckite | Fe3+PO4 · 3H2O |
| 8.CE.60 | Kaňkite | FeAsO4 · 3.5H2O |
| 8.CE.60 | Hilarionite | Fe3+2(SO4)(AsO4)(OH) · 6H2O |
| 8.CE.65 | Steigerite | Al(VO4) · 3H2O |
| 8.CE.70 | Metaschoderite | Al2(PO4)(VO4) · 6H2O |
| 8.CE.70 | Schoderite | Al2(PO4)(VO4) · 8H2O |
| 8.CE.75 | Zigrasite | MgZr(PO4)2 · 4H2O |
| 8.CE.75 | 'UM2009-11-PO:CaHZr' | CaZr[PO4]2 · 4H2O |
| 8.CE.75 | Malhmoodite | FeZr(PO4)2 · 4H2O |
| 8.CE.80 | Santabarbaraite | Fe3+3(PO4)2(OH)3 · 5H2O |
| 8.CE.85 | Metaköttigite | (Zn,Fe,Fe)3(AsO4)2 · 8(H2O,OH) |
| 8.CE.90 | Slavkovite | Cu13(AsO4)6(AsO3OH)4 · 23H2O |
Other Information
Notes:
Soluble in acids.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Hörnesite
mindat.org URL:
https://www.mindat.org/min-1931.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Hörnesite
Reference List:
Haidinger (1860) Jb. geol. Reichsanst. Wien: 11: 41.(as Hörnesit)
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.86
Wolfe, C. W. (1940) Classification of minerals of the type A3(XO4)2·nH2O (concluded) American Mineralogist, 25 (12) 787-809 p.806
Rojo, J.M.; Mesa, J.L.; Pizarro, J.L.; Lezama, L.; Arriortua, M.I.; Rojo, T. (1996) Spectroscopic and magnetic study of the (Mg,M)3(AsO4)2·8H2O (M = Ni2+, Co2+) arsenates. Materials Research Bulletin, 31 (8). 925-934 doi:10.1016/s0025-5408(96)00088-8
Frost, Ray L., Martens, Wayde, Williams, Peter A., Kloprogge, J. Theo (2003) Raman spectroscopic study of the vivianite arsenate minerals. Journal of Raman Spectroscopy, 34 (10). 751-759 doi:10.1002/jrs.1049
Majzlan, Juraj, Reichstein, Anna, Haase, Patrick, Števko, Martin, Sejkora, Jiří, Dachs, Edgar (2024) Thermodynamics of vivianite-group arsenates M3(AsO4)2 ⋅ 8H2O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group. European Journal of Mineralogy, 36 (1). doi:10.5194/ejm-36-31-2024
Localities for Hörnesite
Showing 141 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Australia | |
| S. Mills XRD data |
Austria | |
| Niedermayr et al. (1995) |
| Niedermayr et al. (1995) |
| Blass et al. (1999) |
| Georgian Mining Corporation |
| Majzlan et al. (2021) |
| Kolitsch et al. (2018) |
| Strasser (1989) |
| Strasser (1989) | |
| Coll. D. Lunau | |
| Strasser (1989) | |
| Poeverlein (2008) | |
| Jakely et al. (2015) |
| Jakely (Hrsg.) |
| Schnorrer et al. (2005) |
| Schnorrer+Poeverlein (2005) | |
| Schnorrer et al. (2002) |
| Poeverlein et al. (2007) |
Bolivia | |
| Bentz et al. (2017) |
| Bentz (2017) | |
Brazil | |
| Atencio et al. (2004) |
Chile | |
| Gerhard Möhn collection |
| Gerhard Möhn Collection. Identified by ... |
| XRD and SEM-EDS by Igor V. Pekov |
China | |
| Zhu et al. (2015) +1 other reference |
| Wang et al. (2023) |
| Xianxiao Xiong (1999) |
Czech Republic | |
| Ondruš et al. (1989) |
| Gramblička R. (2014) |
| Palache et al. (1951) +1 other reference | |
| 86. +1 other reference | |
| M.E. Ciriotti |
| Tvrdý +1 other reference |
| |
| Dvořák et al. (Česká republika) |
France | |
| King (n.d.) +1 other reference |
| Bari (1982) |
| Wittern et al. (1997) | |
| Pierre et Terre 1982 | |
| De Bondt (n.d.) | |
| Wittern +1 other reference |
| Bari (1982) | |
| This mine worked the same vein as Gabe ... +2 other references | |
| Kolitsch (1997) |
| Pélisson et al. (1987) |
| Georges FAVREAU collection & EDX ... |
Germany | |
| www.mineralienatlas.de (2020) |
| 50. (in German) +1 other reference |
| American Mineralogist: 76: 2021. |
| |
| Markl (1992) |
| Weiß (1990) |
| Schnorrer-Köhler (1988) | |
| Schnorrer (1993) |
| |
| Weiß (1990) |
| Wittern (2001) |
| Der Aufschluss 2000 (2) |
| Wittern (2001) |
| Henrich (2009) |
| Rolf Golze +3 other references |
| Heinrich et al. (2011) |
| Schnorrer-Köhler (1987) |
| Lapis 1988 (1) |
| Schnorrer-Köhler (1988) |
| Weiß (1990) |
| Schnorrer et al. (1998) |
| Schnorrer et al. (2000) | |
| Weiß (1990) |
| Wittern (2001) |
| Der Aufschluss Vol.55 |
| 58 (in German) +1 other reference |
| Wittern (2001) |
| Desor (04/2020) |
| Witzke (2018) |
| Schnorrer (1995) |
| Hajek (2010) |
| Massanek et al. (2005) |
| Hans-Jürgen Haas collection |
| Witzke et al. (1998) |
Greece | |
| Uwe Kolitsch (unpublished SEM-EDS analyses) |
| |
| Rieck et al. (1999) |
| Rieck et al. (2022) | |
| Kolitsch et al. (2014) |
Iran | |
| Mohsen Mohammadi |
Italy | |
| Carati (1988) |
| Bedognè et al. (2006) |
| Barresi A.A. et al. (Piemonte) |
| Barresi A.A. et al. (Piemonte) | |
| Stara et al. (1994) |
| Caboni et al. (2018) |
| Lecca et al. (2022) |
| G. Ghisolfi collection |
| Biagioni et al. (2017) |
Japan | |
| Kato et al (1988) |
Morocco | |
| Favreau et al. (2006) |
| Favreau et al. (2006) | |
| Favreau et al. (2006) |
Namibia | |
| Gebhard (1999) |
North Macedonia | |
| Rieck (1993) +2 other references |
| Boev et al. (2015) | |
| Kolitsch et al. (2018) |
Poland | |
| Siuda (2014) +1 other reference |
Portugal | |
| Marques de Sá et al. (2010) |
| Alves (n.d.) |
Romania (TL) | |
| Verhandl.kaiserl.-königl.Reichsanst.Wien (1859) +1 other reference |
| Szakáll (2002) | |
| Palache et al. (1951) |
Russia | |
| Pavel M. Kartashov analytical data (2011) |
| Kasatkin et al. (2026) |
Slovakia | |
| Martin Števko |
| Števko et al. (2019) |
| Martin Števko-unpublished |
Spain | |
| Favreau et al. (2013) |
| Rewitzer et al. (2020) |
| Schnorrer (2000) |
| Cesar Menor Salvan |
| Calvo Rebollar (2018) |
| Calvo Rebollar (2012) |
| Joan Abella i Creus (Joanabellacreus@gmail.com) |
| Adrián Pesudo |
Sweden | |
| Holtstam et al. (1999) |
| Gatedal (n.d.) |
| Gatedal (n.d.) +1 other reference | |
Switzerland | |
| Stalder et al. (1998) |
| Schmutz et al. (1986) | |
| Graeser (2008) |
| Ansermet (2012) |
| Ansermet (2012) |
| Stalder et al. (1998) +1 other reference |
| Ansermet (2012) | |
| Ansermet (2012) |
| Ansermet (2012) |
USA | |
| Onac +2 other references |
| Wenrich (1988) +1 other reference |
| Cooper et al. (1986) |
| Castor et al. (2004) |
| Castor et al. (2004) |
| ... +1 other reference |
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Ightem Mine, Ightem, Tansifte Caïdat, Agdz Cercle, Zagora Province, Drâa-Tafilalet Region, Morocco