| Ice | H2O |
| Ilesite | (Mn,Zn,Fe,SO4,nH2O) |
| Ilmenite | FeTiO3 |
| Indicolite | Na(Li,Al)3Al6(SiO3)6(BO3)3(OH)4 |
| Insizwaite | (Pt,Bi,Sb) |
| Iolite | Mg2Al4Si5O18 |
| Iranite | (Pb,Cu,CrO4,Silicate,F,OH) |
| Irarsite | (Ir,Ru,Rh,Pt,As,S) |
| Iridarsenite | (Ir,Ru,As) |
| Isoferroplatinum | (Pt, Pd)3(Fe, Cu) |