Mineral Specimen Images (O)

Olshanskyite: Ca2[B3O3(OH)6]OH·3(H2O)  
Henmilite: Ca2Cu[B(OH)4]2(OH)4

Comments: Milky white olshanskyite hosting crystals of deep blue henmilite to 6 mm across.
Location: Fuka Mine, Bicchu Town, Kawakama Co., Okayama Pref., Japan. Scale: Crystal size 6 mm.
© John Veevaert

Ominelite: (Fe++,Mg)Al3BSiO9

Comments: Photomicrograph of thin-section (plain light) of zoned ominelite (omn) with quartz (qtz) and plagioclase (pl) in alkali feldspar. (AmMin 87:163).
Location: Misen River in Tenkawa, Yoshino, Nara Prefecture, Japan. Scale: Grain size 0.6 mm.
© American Mineralogist

Omphacite: (Ca,Na)(Mg,Fe++,Al)Si2O6

Comments: Dark green crystalline omphacite with glaucophane.
Location: Healdsburg, Sonoma County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Oneillite: Na15Ca3Mn3Fe++3Zr3Nb(Si25O73)(O,OH,H2O)3(OH,Cl)2

Comments: Brownish-yellow grains of oneillite in white K-feldspar from the type locality.
Location: Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry), Mont Saint-Hilaire, Rouville, Montérégie, Québec, Canada. Scale: FOV is 6x5 mm.
© Pavel M. Kartashov

Onoratoite: Sb8O11Cl2

Comments: White crystals of onoratoite with a yellow crystal of sulphur.
Location: Cetine di Cotorniano Mine (Cetine Mine; Tafone Mine), Rosia, Siena, Tuscany, Italy. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Oosterboschite: (Pd,Cu)7Se3

Comments: Polished section showing oosterboschite (metallic yellow) and its alteration product (light brown) as intergranular veinlets surrounding mineralized malachite and quartz (dark grey), and several grains of goethite (light grey).
Location: Copper Hills in the East Pilbara region of Western Australia. (CanMin, v 40:419). Scale: Picture Size 0.56 mm.
© Canadian Mineralogist

Opal: SiO2·n(H2O)

Comments: Colorful white opal on a sandstone matrix.
Location: Queensland, Australia. Scale: 9 x 6 x 3 cm.
© Isaias Casanova / IC Minerals

Opal: SiO2·n(H2O)

Comments: Section of fossilized tree limb that is now completely replaced by black opal.
Location: Virgin Valley District, Humboldt Co., Nevada, USA. Scale: 20x13x11 mm.
© John Betts - Fine Minerals

Opal: SiO2·n(H2O)  
Todorokite: (Na,Ca,K)2(Mn++++,Mn+++)6O12·3-4.5(H2O)

Comments: Dendritic todorokite in white opal.
Location: Brosso Mine, Ivrea, Torino, Piemonte, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Orcelite: Ni5-xAs2 (x=0.23)

Comments: Bronze micro spherical orcelite coated with greenish zaratite.
Location: Tiebaghi Massif, New Caledonia. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Ordonezite: ZnSb2O6

Comments: Greenish, glassy crystals of ordonezite.
Location: Santin mine, Guanajuato, Mexico. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Oregonite: Ni2FeAs2

Comments: Steel gray, altering to brown, rounded oregonite pebble with serpentinite rock.
Location: Josephine Creek, Josephine County, Oregon, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Organovaite-Mn: K2Mn(Nb,Ti)4(Si4O12)2(O,OH)4·6(H2O)

Comments: Crude pink organovaite-Mn pseudomorphs after vuonnemite.
Location: Mt. Karnasurt, Lovozero, Kola Peninsula, Russia. Scale: Specimen Size 1.5x2.5 cm.
© Diederik Visser

Organovaite-Zn: K2Zn(Nb,Ti)4(Si4O12)2(O,OH)4·6(H2O)

Comments: Crude pinkish-brown organovaite-Zn crystals in matrix.
Location: Mt. Karnasurt, Lovozero, Kola Peninsula, Russia. Scale: Specimen Size 1x2.5 cm.
© Diederik Visser

Orickite: CuFeS2·(H2O)

Comments: Black and white image of a polished section showing intergrown crystals of orickite in sodalite (dark). (AmMin 68:246).
Location: Mafic alkalic diatreme at Coyote Peak near Orick, Humboldt County, California, USA. Scale: Image size 0.44 mm.
© American Mineralogist

Orientite: Ca2Mn++Mn+++2Si3O10(OH)4

Comments: Reddish brown massive orientite with pyrolusite.
Location: Oriente Province, Cuba. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Orlandiite: Pb3(Cl,OH)4(SeO3)·(H2O)

Comments: White, acicular crystals of orlandiite.
Location: Baccu Locci Mine, Villaputzu, Cagliari Province, Sardinia, Italy. Scale: Picture size 2 mm.
© Thomas Witzke / Abraxas-Verlag

Orlymanite: Ca4Mn++3Si8O20(OH)6·2(H2O)

Comments: Brown crystalline orlymanite with radiating structure, on inesite.
Location: N'Chwaning Mine, Kuruman, Northern Cape Province, South Africa. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Orpheite: PbAl3(PO4,SO4)2(OH)6 (?)

Comments: Opaque botryoidal orpheite crust.
Location: Near Valmy, Humboldt County, Nevada, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Orpiment: As2S3

Comments: Deep orange-colored orpiment crystal aggregate.
Location: Twin Creeks mine, 62 bench, north of Winnemucca, Humboldt County, Nevada. USA. Scale: 6.5 x 5.5 cm.
© Fabre Minerals