Log InRegister
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 Articles
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsThe ElementsUsersBooks & MagazinesMineral MuseumsMineral Shows & EventsThe Mindat DirectoryDevice Settings
Photo SearchPhoto GalleriesNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day Gallery


This page is currently not sponsored. Click here to sponsor this page.
Hide all sections | Show all sections

About OmsiteHide

bright yellow to amber yellow
Vitreous, Resinous
Specific Gravity:
3.378 (Calculated)
Crystal System:
Named for the closest town, Oms, Pyrénées-Orientales Department, France.
Omsite is a layered double hydroxide (LDH) mineral, with a topology consistent with members of the hydrotalcite supergroup and cualstibite group.

Classification of OmsiteHide

Approval Year:

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
B : Hydroxides with OH, without H2O; insular octahedra

Physical Properties of OmsiteHide

Vitreous, Resinous
Transparent, Translucent
bright yellow to amber yellow
Hardness Data:
3.378 g/cm3 (Calculated)

Optical Data of OmsiteHide

Uniaxial (-)
RI values:
nω = 1.728() nε = 1.660(1)
Max Birefringence:
δ = 0.068
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:

Chemical Properties of OmsiteHide


Crystallography of OmsiteHide

Crystal System:
Class (H-M):
3 - Pyramidal
Space Group:
Cell Parameters:
a = 5.3506(8) Å, c = 19.5802(15) Å
a:c = 1 : 3.659
Unit Cell V:
485.46 ų
Discoidal tablets, flattened on {001}, which form rosettes typically 50–100 μm in diameter.

X-Ray Powder DiffractionHide

Powder Diffraction Data:
4.901 (100)
4.575 (83)
2.3539 (81)
1.8079 (48)
3.781 (34)

Type Occurrence of OmsiteHide

General Appearance of Type Material:
Bright yellow to amber yellow discoidal tablets. Generally crystallizes on siderite.
Place of Conservation of Type Material:
Natural History Museum of Los Angeles County, catalogue numbers 63428 and 63429, and Museum Victoria, registration number M51584.
Associated Minerals at Type Locality:

Synonyms of OmsiteHide

Relationship of Omsite to other SpeciesHide

Other Members of this group:
CualstibiteCu2Al(OH)6[Sb5+(OH)6]Trig. 3 : P3
ZincalstibiteZn2Al(OH)6[Sb5+(OH)6]Trig. 3 : P3

Common AssociatesHide

Associated Minerals Based on Photo Data:
Glaukosphaerite1 photo of Omsite associated with Glaukosphaerite on mindat.org.
Siderite1 photo of Omsite associated with Siderite on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

4.FB.10CualstibiteCu2Al(OH)6[Sb5+(OH)6]Trig. 3 : P3
4.FB.10ZincalstibiteZn2Al(OH)6[Sb5+(OH)6]Trig. 3 : P3

Fluorescence of OmsiteHide

Not fluorescent in either short-wave or long-wave ultraviolet light.

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for OmsiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Berbain, C. & Favreau, G. (2007): Un exemple peu courant de minéralisation nickélifère: le Correc d'en Llinassos à Oms (Pyrénées-Orientales). Le Cahier des Micromonteurs, 95(1), 3-24.
Mills, S.J., Kampf, A.R., Housley, R.M., Favreau, G., Pasero, M., Biagioni, C., Merlino, S., Berbain, C., Orlandi, P. (2012): Omsite, (Ni,Cu)2Fe3+(OH)6[Sb(OH)6], a new member of the cualstibite group from Oms, France. Mineralogical Magazine, 76, 1347-1354.
Mills, S.J., Christy, A.G., Genin, J.-M.R., Kameda, T., Colombo, F. (2012): Nomenclature of the hydrotalcite supergroup: natural layered double hydroxides. Mineralogical Magazine, 76, 1289-1336.

Internet Links for OmsiteHide

Localities for OmsiteHide

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.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for 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 (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
France (TL)
  • Occitanie
    • Pyrénées-Orientales
      • Oms
Mills, S.J., Kampf, A.R., Housley, R.M., Favreau, G., Pasero, M., Biagioni, C., Merlino, S., Berbain, C., Orlandi, P. (2012): Omsite, (Ni,Cu)2Fe3+(OH)6[Sb(OH)6], a new member of the cualstibite group from Oms, France. Mineralogical Magazine, 76, 1347-1354.
  • Attica
    • East Attica
      • Lavreotiki
        • Lavrion District Mines
Rieck, B., Kolitsch, U., Voudouris, P., Giester, G. and Tzeferis, P. (2018): Weitere Neufunde aus Lavrion, Griechenland. Mineralien-Welt 29 (5), 32-77 (in German).
Mineral and/or Locality  
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization. Public Relations by Blytheweigh.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2019, except where stated. Mindat.org relies on the contributions of thousands of members and supporters.
Privacy Policy - Terms & Conditions - Contact Us Current server date and time: March 23, 2019 00:29:12 Page generated: December 24, 2018 20:37:26
Go to top of page