| ianthinite | UO2·5UO3·10H2O |
| ice | H2O |
| idaite | Cu3FeS4 |
| idrialite | C22H14 |
| iimoriite-(Y) | Y2SiO4CO3 |
| ikaite | CaCO3·6H2O |
| ikunolite | Bi4(S,Se)3 |
| ilesite | (Mn,Zn,Fe)SO4·4H2O |
| ilimaussite-(Ce) | Ba2Na4CeFeNb2Si8O28·5H2O |
| ilinskite | NaCu5(SeO3)2O2Cl3 |
| illite | series name |
| ilmajokite | (Na,Ce,Ba)2TiSi3O5(OH)10·nH2O |
| ilmenite | FeTiO3 |
| ilmenite group | |
| ilmenorutile | (Ti,Nb,Fe)3O6 |
| ilsemannite | Mo3O8·nH2O |
| iltisite | HgAgS(Cl,Br) |
| ilvaite | CaFe2FeSi2O7O(OH) |
| imandrite | Na6Ca1.5FeSi6O18 |
| imhofite | Tl6CuAs16S40 |
| imiterite | Ag2HgS2 |
| imogolite | Al2SiO3(OH)4 |
| inaglyite | PbCu3(Ir,Pt)8S16 |
| incaite | (Pb,Ag)4Sn4FeSb2S15 |
| inderborite | CaMgB6O6(OH)10·6H2O |
| inderite | MgB3O3(OH)5·5H2O |
| indialite | Mg2Al4Si5O18 |
| indigirite | Mg2Al2(CO3)4(OH)2·15H2O |
| indite | FeIn2S4 |
| indium | In |
| inesite | Ca2Mn7Si10O28(OH)2·5H2O |
| ingersonite | Ca3MnSb4O14 |
| ingodite | Bi(S,Te) |
| innelite | (Ba,K)4(Na,Ca)3Ti3(Si2O7)2(SO4)2O4 |
| insizwaite | Pt(Bi,Sb)2 |
| intersilite | Na6MnTiSi10O24(OH)4·4H2O |
| inyoite | Ca2B6O6(OH)10·8H2O |
| iodargyrite | AgI |
| iolite | cordierite |
| iowaite | Mg6Fe2(OH)16Cl2·4H2O |
| iquiqueite | K3Na4Mg(CrO4)B24O39OH·12H2O |
| iranite | Pb10Cu(CrO4)6(SiO4)2(F,OH)2 |
| iraqite-(La) | K(La,Ce,Th)2(Ca,Na)4(Si,Al)16O40 |
| irarsite | (Ir,Ru,Rh,Pt)AsS |
| irhtemite | H2Ca4Mg(AsO4)4·4H2O |
| iridarsenite | (Ir,Ru)As2 |
| iridium | Ir |
| iridosmine | osmium |
| iriginite | UO2Mo2O7·3H2O |
| iron | Fe |
| irtyshite | Na2(Ta,Nb)4O11 |
| ishikawaite | (U,Fe,Y,Ca)(Nb,Ta)O4 |
| isoclasite | Ca2PO4OH·2H2O |
| isocubanite | CuFe2S3 |
| isoferroplatinum | Pt3Fe |
| isokite | CaMgPO4F |
| isolueshite | (Na,Ca,La)(Nb,Ti)O3 |
| isomertieite | Pd11Sb2As2 |
| isovite | (Cr,Fe)23C6 |
| itoite | Pb3Ge(SO4)2O2(OH)2 |
| iwakiite | Mn(Fe,Mn)2O4 |
| ixiolite | (Ta,Nb,Sn,Fe,Mn)4O8 |
| izoklakeite | Pb27(Cu,Fe)2(Sb,Bi)19S57 |