| Talc | Mg2Si4O10(OH)
| Tantalaeschynite | (Y,Ca,Ce,Fe,Nd,Th)(Ti,Nb)2(O,OH)6
| | Tantalite | (Fe,Mn)(Ta,Nb)2O6
| | Tanzanite | Ca2Al3(SiO4)3(OH)
| | Teallite | (Pb,Sn,S)
| | Tektite | Si - with Mg, Fe and other impurities
| | Tennantite | Cu12As4S13
| | Testibiopalladite | (Pd,Te,Sb)
| | Tetraauricupride | AuCu
| | Tetradymite | (Bi,Te,S)
| | Tetraferroplatinum | PtFe
| | Tetrahedrite | Cu12Sb4S13
| | Tetrataenite | FeNi
| | Thenardite | Na2SO4
| | Thomsenolite | NaCaAlF6.H2O
| | Tiemannite | (Hg,Se)
| | Tincalconite | Na2B4O7.5H2O
| | Tolovkite | (Ir,Sb,S)
| | Tongbaite | Cr3C2
| | Topaz | Al2SiO4(OH,F)2
| | Torbernite | Cu(UO2)2(PO4)2.8-12H2O
| | Tremolite | Ca2(Mg,Fe)5Si8O22(OH)2
| | Tridydymite | SiO2
| | Trogtalite | (Co,Se)
| | Trona | Na3(HCO3)(CO3).2H2O
| | Tsavorite | Ca3Al2(SiO4)3
| | Tungstenite | (W,S)
| | Tungstite | WO3.H2O
| | Twinnite | Pb(Sb,As)2S4
| | Tyuyamunite | Ca(UO2)2(VO4)2.4H2O
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