Vote for your favorite mineral in #MinCup26! - Erythrite vs. Skutterudite
Pretty pink and poisonous Erythrite is against its shiny silver and structurally-useful Skutterudite.
Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic TimeExplore Fossils
Minerals by PropertiesMinerals by ChemistryMineral Visual ExplorerAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral QuizTime Machine
Photo SearchPhoto GalleriesSearch by ColorPhoto Colour ExplorerNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Omeiite

A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
06379320017271925504374.jpg
Mount Emei
Formula:
OsAs2
Colour:
Dull steel gray
Lustre:
Metallic
Hardness:
7
Specific Gravity:
11.20 (Calculated)
Crystal System:
Orthorhombic
Name:
For Mount Omei (Mount Emei) (in standard Chinese phonetics "Emei", or "Emeishan"), after which the igneous province was named in which the type locality is situated.
Anduoite-Omeiite Series.


Hide all sections | Show all sections

Unique IdentifiersHide

Mindat ID:
2990
Long-form identifier:
mindat:1:1:2990:8

IMA Classification of OmeiiteHide

Classification of OmeiiteHide

Strunz-mindat (2026):
2.EB.15a

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
E : Metal Sulfides, M: S <= 1:2
B : M:S = 1:2, with Fe, Co, Ni, PGE, etc.
Dana 8th ed.:
2.12.2.7

2 : SULFIDES
12 : AmBnXp, with (m+n):p = 1:2
Hey's CIM Ref.:
3.12.58

3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
12 : Sulphides etc. of the platinum metals

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
OmeIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of OmeiiteHide

Lustre:
Metallic
Transparency:
Opaque
Colour:
Dull steel gray
Hardness:
7 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Parallel to elongation
Density:
11.20 g/cm3 (Calculated)

Optical Data of OmeiiteHide

Anisotropism:
Distinct
Reflectivity:
WavelengthR1 (%)R2 (%)
480nm37.86% 39.08%
546nm39.18% 40.43%
589nm42.06% 42.15%
656nm46.35% 48.93%


Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 48.93%.
R1 shown in black, R2 shown in red
Colour in reflected light:
White with a yellow tint in air, milky yellow in oil
Pleochroism:
Weak
Comments:
yellow to grayish yellow

Chemistry of OmeiiteHide

Mindat Formula:
OsAs2
Element Weights:
Element% weight
Os55.938 %
As44.062 %

Calculated from ideal end-member formula.
Os
As
Elements listed:
As, Os - search for minerals with similar chemistry
Common Impurities:
Ir,Ni,Fe,Co

Crystallography of OmeiiteHide

Crystal System:
Orthorhombic
Cell Parameters:
a = 5.409 Å, b = 6.167 Å, c = 3.021 Å
Ratio:
a:b:c = 0.877 : 1 : 0.49
Unit Cell V:
100.77 ų (Calculated from Unit Cell)
Z:
2
Comment:
Point Group: 2/m 2/m 2/m, or mm2.; : Space Group: P nnm or P nn2.

Crystal StructureHide

Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File    Best | x | y | z | a | b | c
Rotation
Stop | Start
Labels
Console Off | On | Grey | Yellow
IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0011946OmeiiteKjekshus A, Rakke T, Andresen A F (1977) Compounds with the marcasite type crystal structure. XII. Structural data for RuP2, RuAs2, RuSb2, OsP2, OsAs2, and OsSb2 Acta Chemica Scandinavica A31 253-2591977synthetic0293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
2.63 Å(100)
1.915 Å(100)
2.67 Å(80)
4.06 Å(60)
2.06 Å(60)
2.01 Å(60)
1.209 Å(60)

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 2: Planetesimal differentiation and alteration4.566-4.550
6 : Secondary asteroid phases4.566-4.560
High-? alteration and/or metamorphism
33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12])

Type Occurrence of OmeiiteHide

Other Language Names for OmeiiteHide

Dutch:Omeiiet
German:Omeiit
Russian:Омейит
Simplified Chinese:峨眉矿
砷锇矿
Spanish:Omeiita

Relationship of Omeiite to other SpeciesHide

Member of:
Löllingite Group
Other Members of Löllingite Group:
AlloclasiteCo1-xFexAsSMon. 2 : P21
AnduoiteRuAs2Orth.
ClinosaffloriteCoAs2Mon. 2/m : P21/m
CostibiteCoSbSOrth. mm2 : Pmn21
LöllingiteFeAs2Orth. mmm(2/m2/m2/m) : Pnnm
NisbiteNiSb2Orth. mmm(2/m2/m2/m) : Pnnm
OeniteCoSbAsOrth.
ParacostibiteCoSbSOrth. mmm(2/m2/m2/m) : Pbca
PararammelsbergiteNiAs2Orth. mmm(2/m2/m2/m) : Pbca
RammelsbergiteNiAs2Orth. mmm(2/m2/m2/m) : Pnnm
Safflorite(Co,Ni,Fe)As2Orth. mmm(2/m2/m2/m) : Pnnm
'UM1998-01-AsSb:CoFeNi'(Fe,Ni)SbAs
Forms a series with:
AnduoiteAnduoite-Omeiite Series

Related Minerals - Strunz-mindat GroupingHide

2.EB.SelenolauriteRuSe2Iso. m3(2/m3) : Pa3
2.EB.AndrieslombaarditeRhSbSIso. 23 : P213
2.EB.Iridarsenite(Ir,Ru)As2Mon. 2/m : P21/b
2.EB.Kanatzidisite(SbBiS3)2Te2Mon. 2/m : P21/m
2.EB.05aVaesiteNiS2Iso. m3(2/m3) : Pa3
2.EB.05aHaueriteMnS2Iso. m3(2/m3) : Pa3
2.EB.05aLauriteRuS2Iso. m3(2/m3) : Pa3
2.EB.05aGaotaiiteIr3Te8Iso. m3(2/m3) : Pa3
2.EB.05aPenroseite(Ni,Co,Cu)Se2Iso. m3(2/m3) : Pa3
2.EB.05aFukuchiliteCu3FeS8Iso. m3(2/m3) : Pa3
2.EB.05aVillamanínite(Cu,Ni,Co,Fe)S2Tric.
2.EB.05aErlichmaniteOsS2Iso. m3(2/m3) : Pa3
2.EB.05aSperrylitePtAs2Iso. m3(2/m3) : Pa3
2.EB.05aGeversitePtSb2Iso. m3(2/m3) : Pa3
2.EB.05aCattieriteCoS2Iso. m3(2/m3) : Pa3
2.EB.05aAurostibiteAuSb2Iso. m3(2/m3) : Pa3
2.EB.05aTrogtaliteCoSe2Iso. m3(2/m3) : Pa3
2.EB.05a v'Cayeuxite'
2.EB.05aKruťaiteCuSe2Iso. m3(2/m3) : Pa3
2.EB.05aPyriteFeS2Iso. m3(2/m3) : Pa3
2.EB.05aInsizwaitePtBi2Iso. m3(2/m3) : Pa3
2.EB.05bBambollaiteCu(Se,Te)2Tet.
2.EB.05aDzharkeniteFeSe2Iso. m3(2/m3) : Pa3
2.EB.10aMarcasiteFeS2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.10eParacostibiteCoSbSOrth. mmm(2/m2/m2/m) : Pbca
2.EB.10fOeniteCoSbAsOrth.
2.EB.10ePararammelsbergiteNiAs2Orth. mmm(2/m2/m2/m) : Pbca
2.EB.10aMattagamiteCoTe2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.10aFrohbergiteFeTe2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.10dCostibiteCoSbSOrth. mm2 : Pmn21
2.EB.10bAlloclasiteCo1-xFexAsSMon. 2 : P21
2.EB.10cGlaucodot(Co0.50Fe0.50)AsSOrth. mm2 : Pmn21
2.EB.10aPetříčekiteCuSe2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.10aKulleruditeNiSe2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.10aFerroseliteFeSe2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.15bSeinäjokiteFeSb2Orth.
2.EB.15aRammelsbergiteNiAs2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.15aClinosaffloriteCoAs2Mon. 2/m : P21/m
2.EB.15cPaxiteCuAs2Mon. 2/m : P21/b
2.EB.15aNisbiteNiSb2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.15aLöllingiteFeAs2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.15aSafflorite(Co,Ni,Fe)As2Orth. mmm(2/m2/m2/m) : Pnnm
2.EB.15aAnduoiteRuAs2Orth.
2.EB.20ArsenopyriteFeAsSMon. 2/m : P21/b
2.EB.20Ruarsite(Ru,Os)AsSMon.
2.EB.20Osarsite(Os,Ru)AsSMon.
2.EB.20GudmunditeFeSbSMon. 2/m : P21/b
2.EB.25MayingiteIrBiTeIso. m3(2/m3) : Pa3
2.EB.25MaslovitePtBiTeIso. 23 : P213
2.EB.25ParagersdorffiteNi(As,S)2Iso. m3(2/m3) : Pa3
2.EB.25OrthogersdorffiteNiAsSOrth. mm2 : Pca21
2.EB.25SulfopadmaitePdBiSIso. 23 : P213
2.EB.25JolliffeiteNiAsSeIso. m3(2/m3) : Pa3
2.EB.25CobaltiteCoAsSOrth. mm2 : Pca21
2.EB.25GuixiangiteNiBiSIso. 23 : P213
2.EB.25TestibiopalladitePdSbTeIso.
2.EB.25 va'Antimony-bearing Gersdorffite'Ni(As,Sb)S
2.EB.25KalungaitePdAsSeIso. m3(2/m3) : Pa3
2.EB.25Hollingworthite(Rh,Pt,Pd)AsSIso. m3(2/m3) : Pa3
2.EB.25MicheneritePdBiTeIso. 23 : P213
2.EB.25GersdorffiteNiAsSIso. 23 : P213
2.EB.25MilotaitePdSbSeIso. 23 : P213
2.EB.25TolovkiteIrSbSIso.
2.EB.25'Platarsite'Pt(As,S)2Iso. m3(2/m3) : Pa3
2.EB.25WillyamiteCoSbS
2.EB.25ChangchengiteIrBiSIso. 23 : P213
2.EB.25KvačekiteNiSbSeIso. 23 : P213
2.EB.25KrutoviteNiAs2Iso. 23 : P213
2.EB.25PadmaitePdBiSeIso. 432
2.EB.25UllmanniteNiSbSIso. 23 : P213
2.EB.25Irarsite(Ir,Ru,Rh,Pt)AsSIso. m3(2/m3) : Pa3
2.EB.30UrvantsevitePd(Bi,Pb)2Tet. 4/mmm(4/m2/m2/m) : I4/mmm
2.EB.35RheniiteReS2Tric. 1 : P1

Other InformationHide

Notes:
Insoluble in HCl and HNO3 and dissolves with difficulty in aqua regia.
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 OmeiiteHide

References for OmeiiteHide

Localities for OmeiiteHide

Showing 15 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Hide all sections | Show all sections

Locality ListHide

- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
Brazil
 
  • Minas Gerais
de Almeida et al. (2007)
Marchetto (1990)
Chile
 
  • Araucanía
    • Cautín Province
González-Jiménez et al. (2016)
Galdames et al. (2010) +1 other reference
China (TL)
 
  • Sichuan
    • Garzê Autonomous Prefecture (Ganzi Autonomous Prefecture)
      • Danba Co.
        • Yangliuping Cu-Ni-PGE ore field
Ren et al. (1978) +3 other references
Greece
 
  • Thessaly
    • Trikala
      • Meteora
Kapsiotis et al. (2011)
India
 
  • Odisha
    • Jajapur (Jajpur) District
      • Sukinda ultramafic complex
        • Sukinda Valley
          • Sukinda Mines
Raju et al. (2007)
Kazakhstan
 
  • Aktobe Region
    • Kargaly District
Melcher et al. (1997) +1 other reference
Russia
 
  • Irkutsk Oblast
Kolotilina et al. (2019)
    • Uda–Biryusa district
Shvedov et al. (2017)
Podlipsky et al. (2015)
Kolotilina et al. (2019) +1 other reference
  • Tuva
    • Kaa-Khemsky District
      • Kaakhem ophiolite belt
Oidup et al. (2012)
Ukraine
 
  • Cherkasy Oblast
    • Zvenyhorodka Raion
Gornostayev et al. (2002)
USA
 
  • Pennsylvania
    • Chester County
Smith and Barnes (2011)
Quick NavTopUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesRelationshipsStrunz-MindatOther InformationInternet Links References Localities Locality List
 
and/or  
Mindat.org® is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Mindat® and mindat.org® are registered trademarks of the Hudson Institute of Mineralogy.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2026, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph and Ida Chau.
Content on this site may not be used to train, fine-tune, or otherwise develop artificial intelligence or machine learning models without prior written permission - see our Terms & Conditions.
To cite: Ralph, J., Von Bargen, D., Martynov, P., Zhang, J., Que, X., Prabhu, A., Morrison, S. M., Li, W., Chen, W., & Ma, X. (2025). Mindat.org: The open access mineralogy database to accelerate data-intensive geoscience research. American Mineralogist, 110(6), 833–844. doi:10.2138/am-2024-9486.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: September 2, 2026 03:01:29 Page updated: August 24, 2026 09:22:34
Go to top of page