| Qandilite | (Mg,Fe³⁺)₂(Ti,Fe³⁺,Al)O₄ | Cubic | 7.0 | — |
| Qaqarssukite-(Ce) | BaCe(CO₃)₂F | Trigonal | — | — |
| Qatranaite | CaZn₂(OH)₆(H₂O)₂ | Monoclinic | — | — |
| Qeltite | Ca₃TiSi₂(Fe³⁺₂Si)O₁₄ | Trigonal | — | — |
| Qilianshanite | NaH₄(CO₃)BO₃)·2H₂O | Monoclinic | — | — |
| Qingheiite | NaNaMn(MgAl)(PO₄)₃ | Monoclinic | — | — |
| Qingsongite | BN | Cubic | — | — |
| Qitianlingite | Fe²⁺₂Nb₂W⁶⁺O₁₀ | Orthorhombic | — | — |
| Qiumingite | Pb₃(Zn₂Fe³⁺)Sb⁵⁺P₂O₁₄ | Trigonal | — | — |
| Quadratite | AgCdAsS₃ | Tetragonal | — | 5.31 g/cm³ |
| Quadridavyne | [(Na,K)₆Cl₂][Ca₂Cl₂][(Si₆Al₆O₂₄)] | Hexagonal | — | — |
| Quadruphite | Na₆Na₂(CaNa)₂Na₂Ti₂Na₂Ti₂(Si₂O₇)₂(PO₄)₄O₄F₂ | Triclinic | — | — |
| Quartz | SiO₂ | Trigonal | 7.0 | 2.65 g/cm³ |
| Quatrandorite | AgPbSb₃S₆ | Monoclinic | — | — |
| Queitite | Zn₂Pb₄(Si₂O₇)(SiO₄)(SO₄) | Monoclinic | 4.0 | 5.85 g/cm³ |
| Quenselite | PbMn³⁺O₂(OH) | Monoclinic | 2.5 | — |
| Quenstedtite | Fe₂(SO₄)₃·11H₂O | Triclinic | 2.5 | — |
| Quetzalcoatlite | Cu²⁺₃Zn₆Te⁶⁺₂O₁₂(OH)₆·(Ag,Pb,☐)Cl | Trigonal | 3.0 | — |
| Quijarroite | Cu₆HgPb₂Bi₄Se₁₂ | Orthorhombic | — | — |
| Quintinite | Mg₄Al₂(OH)₁₂(CO₃)·3H₂O | Hexagonal | 2.0 | — |
| Qusongite | WC | Hexagonal | — | 15.55 g/cm³ |