| Mineral | Formula | Crystal System | Mindat |
|---|
| Acanthite | Ag2S | Monoclinic | Mindat.org |
| Actinolite | Ca2(Mg,Fe2+)5(Si8O22)(OH)2 | Monoclinic | Mindat.org |
| Adamite | Zn2(AsO4)(OH) | Orthorhombic | Mindat.org |
| Aegirine | NaFe3+(Si2O6) | Monoclinic | Mindat.org |
| Aenigmatite | Na2Fe2+5Ti(Si6O18)O2 | Triclinic | Mindat.org |
| Aerinite | Ca5(Fe3+,Al,Fe2+,Mg)(Al,Mg)6[HSi12O36(OH)12](CO3)1.2 • 12(H2O) | Monoclinic | Mindat.org |
| Afghanite | (Na,Ca,K)8[(Cl2,SO4,CO3)3|Al6Si6O24] • 0.5(H2O) | Hexagonal | Mindat.org |
| Agardite-(Ce) | CeCu6(AsO4)3(OH)6 • 3H2O | Hexagonal | Mindat.org |
| Agardite-(La) | (La,Ce)Cu6(AsO4)(OH)6 • 3(H2O) | Hexagonal | Mindat.org |
| Agrellite | NaCa2[F | Si4O10] | Triclinic | Mindat.org |
| Ajoite | (K,Na)3Cu20Al3Si29O76(OH)16 • ~8(H2O) | Triclinic | Mindat.org |
| Albite | NaAlSi3O8 | Triclinic | Mindat.org |
| Allanite-(Ce) | {CaCe}{Al2Fe2+}(Si2O7)(SiO4)O(OH) | Monoclinic | Mindat.org |
| Almandine | Fe2+3Al2(SiO4)3 | Isometric | Mindat.org |
| Alunogen | Al2(SO4)3 • 17H2O | Triclinic | Mindat.org |
| Amber | [C,H,O] | Amorphous | Mindat.org |
| Ammineite | CuCl2(NH3)2 | Orthorhombic | Mindat.org |
| Analcime | Na(AlSi2O6) · H2O | Triclinic | Mindat.org |
| Anatase | TiO2 | Tetragonal | Mindat.org |
| Andersonite | Na2Ca(UO2)(CO3)3 • 6(H2O) | Trigonal | Mindat.org |
| Andorite | PbAgSb3S6 | Orthorhombic | Mindat.org |
| Andradite | Ca3Fe3+2(SiO4)3 | Isometric | Mindat.org |
| Anglesite | PbSO4 | Orthorhombic | Mindat.org |
| Ankerite | Ca(Fe2+,Mg,Mn)(CO3)2 | Trigonal | Mindat.org |
| Annabergite | Ni3(AsO4)2 · 8H2O | Monoclinic | Mindat.org |
| Annite | KFe²⁺3(AlSi₃O₁₀)(OH)₂ | Monoclinic | Mindat.org |
| Anorthite | CaAl2Si2O8 | Triclinic | Mindat.org |
| Anthophyllite | (Mg,Fe2+)2(Mg,Fe2+)5Si8O22(OH)2 | Orthorhombic | Mindat.org |
| Antigorite | (Mg,Fe2+)3Si2O5)(OH)4 | Monoclinic | Mindat.org |
| Antimony | Sb | Trigonal | Mindat.org |
| Antipinite | KNa3Cu2(C2O4)4 | Triclinic | Mindat.org |
| Antlerite | Cu3[(OH)4|SO4] | Orthorhombic | Mindat.org |
| Apachite | Cu9Si10O29 · 11H2O | Monoclinic | Mindat.org |
| Apophyllite | KCa4(Si4O10)2F • 8(H2O) | Tetragonal | Mindat.org |
| Aragonite | CaCO3 | Orthorhombic | Mindat.org |
| Aravaipaite | Pb3AlF9 · H2O | Triclinic | Mindat.org |
| Arfvedsonite | NaNa2Fe2+4Fe3+(Si8O22)(OH)2 | Monoclinic | Mindat.org |
| Argentite | Ag2S | Isometric | Mindat.org |
| Arsenopyrite | FeAsS | Monoclinic | Mindat.org |
| Arthurite | CuFe3+2(AsO4)2(OH)2 · 4H2O | Monoclinic | Mindat.org |
| Astrophyllite | (K,Na)3(Fe,Mn)7Ti2Si8O24(O,OH)7 | Triclinic | Mindat.org |
| Atacamite | Cu2Cl(OH)3 | Orthorhombic | Mindat.org |
| Augelite | Al2[(OH)3|PO4] | Monoclinic | Mindat.org |
| Aurichalcite | (Zn,Cu)5(CO3)2(OH)6 | Monoclinic | Mindat.org |
| Austinite | CaZn(AsO4)(OH) | Orthorhombic | Mindat.org |
| Autunite | Ca(UO2)2(PO4)2 · 10-12H2O | Orthorhombic | Mindat.org |
| Axinite | (Ca,Fe,Mn)3Al2BO3Si4O12OH | Triclinic | Mindat.org |
| Axinite-(Mn) | Ca2Mn2+Al2BSi4O15(OH) | Triclinic | Mindat.org |
| Azurite | Cu3(CO3)2(OH)2 | Monoclinic | Mindat.org |
| Babingtonite | Ca2(Fe,Mn)FeSi5O14O(OH) | Triclinic | Mindat.org |
