Obertiite IMA1998-046
Ferric-nyboite
NaNa2(Mg3Fe+++Ti)Si8O22(O,F,OH)2
Oboyerite Pb6H6(Te++++O3)3(Te++++++O6)2·2(H2O)
Obradovicite H4(K,Na)Cu++Fe+++2(AsO4)(MoO4)5·12(H2O)
Odanielite O'danielite
Na(Zn,Mg)3H2(AsO4)3
Odinite (Fe+++,Mg,Al,Fe++,Ti,Mn)2.5(Si,Al)2O5(OH)4
Odintsovite IMA1994-052
K2Na4Ca3Ti2Be4Si12O38
Oenite IMA1995-007
CoSbAs
Offretite (K2,Ca,Mg)2.5Al5Si13O36·15(H2O)
Ogdensburgite Ca2(Zn,Mn)Fe+++4(AsO4)4(OH)6·6(H2O)
Ohmilite Sr3(Ti,Fe+++)(Si2O6)2(O,OH)·2-3(H2O)
Ojuelaite ZnFe+++2(AsO4)2(OH)2·4(H2O)
Okanoganite-(Y) (Na,Ca)3(Y,Ce)12Si6B2O27F14
Okayamalite IMA1997-002
Ca2B2SiO7
Okenite Ca3[Si6O15]·6(H2O)
Okhotskite-(Mg) Ca3(Mg,Mn++)(Mn+++,Al,Fe+++)(SiO4)(Si2O7)(OH)2·(H2O)
Okhotskite-(Mn++) Ca2(Mn++,Mg)(Mn+++,Al,Fe+++)Si3O10(OH)4
Oldhamite (Ca,Mg,Fe,Mn)S
Olekminskite Sr(Sr,Ca,Ba)(CO3)2
Olenite Tourmaline
NaAl3Al6(BO3)3(Si6O18)(O,OH)4
Olgite Na(Sr,Ba)PO4
Oligoclase Ab80
Sunstone
An20
(Na,Ca)(Si,Al)4O8
Olivenite Wood arsenate
Wood copper
Cu2AsO4(OH)
Olivine Chrysolite - light yellowish green
Peridot
(Mg,Fe)2SiO4
Olkhonskite IMA1993-035
(Cr+++,V+++)2Ti3O9
Olmsteadite KFe++2(Nb,Ta)(PO4)2O2·2(H2O)
Olsacherite Pb2(SeO4)(SO4)
Olshanskyite Ca2[B3O3(OH)6]OH·3(H2O)
Olympite LiNa5(PO4)2
Omeiite (Os,Ru)As2
Ominelite IMA1999-025
(Fe++,Mg)Al3BSiO9
Omphacite (Ca,Na)(Mg,Fe++,Al)Si2O6
Oneillite IMA1998-064
Na15Ca3Mn3Fe++3Zr3Nb(Si25O73)(O,OH,H2O)3(OH,Cl)2
Onoratoite Sb8O11Cl2
Oosterboschite (Pd,Cu)7Se3
Opal Hydrophane - porous
Hyalite - glassy
Prase - green
Precious opal - opalescent
Fire Opal - red
SiO2·n(H2O)
Orcelite Ni5-xAs2 (x=0.23)
Ordonezite ZnSb2O6
Orebroite-III Oerebroite
Mn++6(Fe+++,Sb+++++)2Si2(O,OH)14
Orebroite-VIII Oerebroite
Mn++3(Sb+++++,Fe+++)SiO4(O,OH)3
Oregonite Ni2FeAs2
Orickite CuFeS2·(H2O)
Orientite Ca2Mn++Mn+++2Si3O10(OH)4
Orlandiite IMA1998-038
Pb3(Cl,OH)4(SeO3)·(H2O)
Orlymanite Ca4Mn++3Si8O20(OH)6·2(H2O)
Orpheite PbAl3(PO4,SO4)2(OH)6 (?)
Orpiment As2S3
Orschallite Ca3(SO3)2SO4·12(H2O)
Orthobrannerite U++++U++++++Ti4O12(OH)2
Orthochamosite (Fe++,Mg,Fe+++)5Al(Si3Al)O10(OH,O)8
Orthochevkinite (Ce,La,Ca,Na,Th)4(Fe++,Mg)2(Ti,Fe+++)3Si4O22
Orthochrysotile Asbestos
Chrysotile
Mitaxite - splintery
Mg3Si2O5(OH)4
Orthoclase Adularia
Orthose
KAlSi3O8
Orthoericssonite BaMn2(Fe+++O)Si2O7(OH)
Orthojoaquinite-(Ce) NaFe++Ba2Ce2Ti2[Si4O12]2 O2(OH)·(H2O)
Orthojoaquinite-(La) IMA2000-D
Ba2Na(La,Ce)2Fe++Ti2Si8O26(OH,O,F)·H2O
Orthominasragrite IMA2000-018
VO(SO4)·5(H2O)
Orthopinakiolite (Mg,Mn++)2Mn+++BO5
Orthoserpierite Ca(Cu,Zn)4(SO4)2(OH)6·3(H2O)
Orthowalpurgite IMA1994-024
(UO2)Bi4O4(AsO4)2·2(H2O)
Osarizawaite PbCuAl2(SO4)2(OH)6
Osarsite (Os,Ru)AsS
Osbornite TiN
Osmium Nevyanakite
Rutheniridosmium
Iridosmine
Siserskite
(Os,Ir)
Osumilite-(Fe) (K,Na)(Fe++,Mg)2(Al,Fe+++)3(Si,Al)12O30
Osumilite-(Mg) (K,Na)(Mg,Fe++)2(Al,Fe+++)3(Si,Al)12O30
Oswaldpeetersite IMA2000-034
(UO2)2CO3(OH)2·4(H2O)
Otavite CdCO3
Otjisumeite PbGe4O9
Ottemannite Sn2S3
Ottrelite (Mn,Fe++,Mg)2Al4Si2O10(OH)4
Otwayite Ni2(CO3)(OH)2·(H2O)
Oulankaite IMA1990-055
Oulongaite
(Pd,Pt)5(Cu,Fe)4SnTe2S2
Ourayite Pb4Ag3Bi5S13
Oursinite (Co,Mg)(H3O)2[(UO2)SiO4]2·3(H2O)
Overite CaMgAl(PO4)2(OH)·4(H2O)
Owensite IMA1993-061
(Ba,Pb)6(Cu,Fe,Ni)25S27
Owyheeite Pb7Ag2(Sb,Bi)8S20
Oxammite (NH4)2(C2O4)·(H2O)
Oxiberaunite (Fe+++,Mn+++)Fe+++5(PO4)4O(OH)4·6(H2O)
Oyelite Ca10B2Si8O29·12(H2O)