Beginning with X.
- XanthiositeNi3(AsO4)2Mineralphosphate
- XanthitaneTiO2Variety—
- Xanthite(Ca,Na,◻)19(Al,Mg,Fe3+)13(◻,B,Al,Fe3+)5(Si2O7)4(SiO4)10(OH,F,O)10Variety—
- XanthoconiteAg3AsS3Mineralsulfide
- XanthoxeniteCa4Fe3+2(PO4)4(OH)2 · 3H2OMineralphosphate
- XenophylliteNa4Fe7(PO4)6Mineralphosphate
- Xenotime-(Gd)Gd(PO4)Mineralphosphate
- Xenotime-(Y)Y(PO4)Mineralphosphate
- Xenotime-(Yb)Yb(PO4)Mineralphosphate
- XiangjiangiteFe3+(UO2)4(PO4)2(SO4)2(OH) · 22H2OMineralphosphate
- Xianhuaite-(Ce)K2CeNb5O15Mineraloxide
- Xianhuaite-(La)K2LaNb5O15Mineraloxide
- XieiteFeCr2O4Mineraloxide
- XiexiandeiteSiO2Mineraloxide
- XifengiteFe5Si3Mineralnative
- XilingolitePb3Bi2S6Mineralsulfide
- XimengiteBi(PO4)Mineralphosphate
- XingzhongitePb2+Ir3+2S4Mineralsulfide
- XitieshaniteFe3+(SO4)Cl · 6H2OMineralsulfate
- XocolatliteCa2Mn4+2Te6+2O12 · H2OMineralsulfate
- XocomecatliteCu3(Te6+O4)(OH)4Mineralsulfate
- XonotliteCa6Si6O17(OH)2Mineralsilicate
- XuiteCa3Fe2[AlO3(OH)]3Mineraloxide
- XuwenyuaniteAg9Fe3+Te2S4Mineralsulfide