| Jacobsite | Mn²⁺Fe³⁺₂O₄ | Cubic | — | — |
| Jacobsite-Q | — | Tetragonal | — | — |
| Jacquesdietrichite | Cu₂(H₂BO₃)(OH)₃ | Orthorhombic | 2.0 | — |
| Jacutingaite | Pt₂HgSe₃ | Trigonal | — | 10.58 g/cm³ |
| Jadarite | LiNaB₃SiO₇(OH) | Monoclinic | — | 2.37 g/cm³ |
| Jadeite | NaAlSi₂O₆ | Monoclinic | — | — |
| Jaffeite | Ca₆Si₂O₇(OH)₆ | Trigonal | — | — |
| Jagoite | Pb₁₈Fe³⁺₄[Si₄(Si,Fe³⁺)₆][Pb₄Si₁₆(Si,Fe)₄]O₈₂Cl₆ | Hexagonal | — | — |
| Jagowerite | — | Triclinic | — | — |
| Jagüéite | — | Monoclinic | — | — |
| Jahnsite-(CaFeMg) | CaFe²⁺Mg₂Fe³⁺₂(PO₄)₄(OH)₂·8H₂O | Monoclinic | — | — |
| Jahnsite-(CaMnFe) | CaMn²⁺Fe²⁺₂Fe³⁺₂(PO₄)₄(OH)₂(H₂O)₈ | Monoclinic | — | — |
| Jahnsite-(CaMnMg) | CaMn²⁺Mg₂Fe³⁺₂(PO₄)₄(OH)₂(H₂O)₈ | Monoclinic | — | — |
| Jahnsite-(CaMnMn) | CaMn²⁺Mn²⁺₂Fe³⁺₂(PO₄)₄(OH)₂(H₂O)₈ | Monoclinic | — | — |
| Jahnsite-(CaMnZn) | — | Monoclinic | — | — |
| Jahnsite-(MnMnFe) | Mn²⁺Mn²⁺Fe²⁺₂Fe³⁺₂(PO₄)₄(OH)₂·8H₂O | Monoclinic | — | — |
| Jahnsite-(MnMnMg) | Mn²⁺Mn²⁺Mg₂Fe³⁺₂(PO₄)₄(OH)₂(H₂O)₈ | Monoclinic | — | — |
| Jahnsite-(MnMnMn) | {Mn²⁺}{Mn²⁺}{Mn²⁺₂}{Fe³⁺₂}(PO₄)₄(OH)₂·8H₂O | Monoclinic | — | — |
| Jahnsite-(MnMnZn) | Mn²⁺Mn²⁺Zn₂Fe³⁺₂(PO₄)₄(OH)₂(H₂O)₈ | Monoclinic | — | — |
| Jahnsite-(NaFeMg) | NaFe³⁺Mg₂Fe³⁺₂(PO₄)₄(OH)₂·8H₂O | Monoclinic | — | — |
| Jahnsite-(NaMnMg) | {(Na,Ca)}{(Mn²⁺,Fe³⁺)}{(Mg,Fe³⁺)₂}{Fe³⁺₂}(PO₄)₄(OH)₂(H₂O)₈ | Monoclinic | — | — |
| Jahnsite-(NaMnMn) | — | Monoclinic | — | — |
| Jaipurite | CoS | Hexagonal | — | — |
| Jakobssonite | CaAlF₅ | Monoclinic | — | 2.94 g/cm³ |
| Jalpaite | Ag₃CuS₂ | Tetragonal | — | — |
| Jamborite | Ni(OH,S,O)₂·nH₂O | Hexagonal | — | — |
| Jamesite | Pb₂Zn(Fe²⁺,Zn)₂Fe³⁺₄(AsO₄)₄(OH)₁₀ | Triclinic | 3.0 | 5.08 g/cm³ |
| Jamesonite | Pb₄FeSb₆S₁₄ | Monoclinic | 2.5 | — |
| Janchevite | Pb₇V₅+(O₈.₅☐₀.₅)Cl₂ | Tetragonal | — | — |
| Janggunite | (Mn⁴⁺,Mn²⁺,Fe³⁺)₆O₈(OH)₆ | Orthorhombic | — | — |
| Janhaugite | (Na,Ca)₃(Mn²⁺,Fe²⁺)₃(Ti,Zr,Nb)₂(Si₂O₇)₂O₂(OH,F)₂ | Monoclinic | — | — |
| Jankovićite | — | Triclinic | — | — |
| Jarandolite | CaB₃O₄(OH)₃ | Monoclinic | — | 2.48 g/cm³ |
| Jarlite | Na₂(Sr,Na)₁₄Mg₂Al₁₂F₆₄(OH,H₂O)₄ | Monoclinic | — | — |
| Jarosewichite | Mn2+3Mn3+(AsO4)(OH)6 | Orthorhombic | 4.0 | — |
| Jarosite | KFe³⁺₃(SO₄)₂(OH)₆ | Hexagonal | — | — |
| Jaskólskiite | CuₓPb₂₊ₓ(Sb,Bi)₂₋ₓS₅ (x~0.2) | Orthorhombic | 4.0 | — |
| Jasmundite | Ca₁₁(SiO₄)₄O₂S | Tetragonal | — | — |
| Jasonsmithite | — | Monoclinic | — | — |
| Jasrouxite | Ag₁₆Pb₄(Sb₂₅As₁₅)S₇₂ | Triclinic | — | — |
| Jaszczakite | [Bi₃S₃][AuS₂] | Orthorhombic | — | — |
| Javorieite | KFeCl₃ | Orthorhombic | — | — |
| Jeanbandyite | Fe³⁺xFe²⁺₁-xSn(OH)₆-xOx | Tetragonal | — | — |
| Jeankempite | Ca₅(AsO₄)₂(AsO₃OH)₂(H₂O)₇ | Triclinic | — | — |
| Jedwabite | Fe₇Ta₃ | Hexagonal | 6.5 | — |
| Jeffbenite | Mg₃Al₂Si₃O₁₂ | Tetragonal | — | — |
| Jeffreyite | (Ca,Na)₂(Be,Al)(Si₂O₇,HSi₂O₇) | Orthorhombic | — | — |
| Jennite | Ca₉Si₆O₁₆(OH)₁₀·6H₂O | Triclinic | 3.5 | — |
| Jensenite | Cu²⁺₃Te⁶⁺O₆(H₂O)₂ | Monoclinic | — | — |
| Jentschite | TlPbAs₂SbS₆ | Monoclinic | — | — |
| Jeppeite | — | Monoclinic | — | — |
| Jeremejevite | Al₆(BO₃)₅F₃ | Hexagonal | — | 3.18 g/cm³ |
| Jerrygibbsite | Mn²⁺₉(SiO₄)₄(OH)₂ | Orthorhombic | — | — |
| Jervisite | NaScSi₂O₆ | Monoclinic | 6.0 | 3.09 g/cm³ |
| Ježekite | Na₈[(UO₂)(CO₃)₃](SO₄)₂·3H₂O | Hexagonal | — | — |
| Jianmuite | ZrTi⁴⁺Ti³⁺₅Al₃O₁₆ | Tetragonal | — | — |
| Jianshuiite | MgMn⁴⁺₃O₇(H₂O)₃ | Triclinic | — | — |
| Jimboite | Mn²⁺₃[BO₃]₂ | Orthorhombic | 5.5 | — |
| Jimkrieghite | Ca(C₂H₃O₃)₂ | Orthorhombic | — | — |
| Jimthompsonite | Mg₅Si₆O₁₆(OH)₂ | Orthorhombic | — | — |
| Jingsuiite | TiB₂ | Hexagonal | — | 4.51 g/cm³ |
| Jinshajiangite | BaNa(Fe²⁺)₄Ti₂(Si₂O₇)₂O₂(OH)₂F | Monoclinic | — | — |
| Jinxiuite | Ni₁₈Bi₂SbAsS₁₆ | Tetragonal | — | — |
| Joanneumite | Cu(C₃N₃O₃H₂)₂(NH₃)₂ | Triclinic | — | — |
| Joaquinite-(Ce) | NaBa₂Ce₂FeTi₂[Si₄O₁₂]₂O₂(OH,F)·H₂O | Monoclinic | — | — |
| Joegoldsteinite | MnCr₂S₄ | Cubic | — | 3.67 g/cm³ |
| Joesmithite | PbCa₂(Mg₃Fe³⁺₂)(Be₂Si₆)O₂₂(OH)₂ | Monoclinic | 5.5 | — |
| Johachidolite | CaAlB₃O₇ | Orthorhombic | — | — |
| Johanngeorgenstadtite | — | Monoclinic | — | — |
| Johannite | Cu(UO₂)₂(SO₄)₂(OH)₂·8H₂O | Triclinic | 2.0 | — |
| Johannsenite | CaMn²⁺Si₂O₆ | Monoclinic | 6.0 | — |
| Johillerite | NaCuMg₃(AsO₄)₃ | Monoclinic | 3.0 | — |
| Johnbaumite | Ca₅(AsO₄)₃OH | Hexagonal | 4.5 | — |
| Johninnesite | Na₂Mn²⁺₉Mg₇(OH)₈[AsO₄]₂[Si₆O₁₇]₂ | Triclinic | — | — |
| Johnjamborite | — | Triclinic | — | — |
| Johnkoivulaite-(Cs) | — | Hexagonal | — | — |
| Johnsenite-(Ce) | Na₁₂Ce₃Ca₆Mn₃Zr₃WSi₂₅O₇₃(CO₃)(OH)₂ | Trigonal | — | — |
| Johnsomervilleite | Na₁₀Ca₆Mg₁₈Fe²⁺₂₅(PO₄)₃₆ | Trigonal | — | — |
| Johntomaite | — | Monoclinic | — | — |
| Johnwalkite | — | Orthorhombic | — | — |
| Joliotite | (UO₂)CO₃·nH₂O | Orthorhombic | — | — |
| Jolliffeite | NiAsSe | Cubic | — | 7.09 g/cm³ |
| Jonassonite | Au(Bi,Pb)₅S₄ | Monoclinic | — | — |
| Jonesite | KBa₂Ti₂(Si₅Al)O₁₈·nH₂O | Orthorhombic | — | — |
| Jonlarsenite | Al₄Cu₉ | Cubic | — | — |
| Joosteite | Mn²⁺Mn³⁺O(PO₄) | Monoclinic | 4.0 | 4.13 g/cm³ |
| Jordanite | Pb₁₄(As,Sb)₆S₂₃ | Monoclinic | — | — |
| Jordanówite | Zr(Ti³⁺Zr)Ti³⁺₄AlO₁₆ | Tetragonal | — | — |
| Jordisite | MoS₂ | Amorphous | — | 4.67 g/cm³ |
| Joséite-A | Bi₄TeS₂ | — | — | — |
| Joséite-B | Bi₄Te₂S | Trigonal | — | — |
| Joteite | Ca₂CuAl[AsO₄][AsO₃(OH)]₂(OH)₂·5H₂O | Triclinic | — | — |
| Jouravskite | Ca₃Mn₄+(SO₄)(CO₃)(OH)₆·12H₂O | Hexagonal | — | — |
| Joëlbruggerite | Pb₃Zn₃(Sb⁵⁺,Te⁶⁺)As₂O₁₃(OH,O) | Trigonal | — | — |
| Juabite | — | Triclinic | — | — |
| Juangodoyite | Na₂Cu(CO₃)₂ | Monoclinic | — | 2.85 g/cm³ |
| Juanitaite | — | Tetragonal | — | — |
| Juanite | Ca₁₀Mg₄Al₂Si₁₁O₃₉·4H₂O or near | — | — | — |
| Juansilvaite | Na₅Al₃[AsO₃(OH)]₄[AsO₂(OH)₂]₂(SO₄)₂·4H₂O | Monoclinic | — | — |
| Julgoldite-(Fe2+) | Ca₂Fe²⁺Fe³⁺₂(Si₂O₇)(SiO₄)(OH)₂·H₂O | Monoclinic | — | — |
| Julgoldite-(Fe3+) | — | Monoclinic | — | — |
| Julgoldite-(Mg) | Ca₂MgFe³⁺₂(Si₂O₇)(SiO₄)(OH)₂·H₂O | Monoclinic | — | — |
| Julienite | Na₂[Co(SCN)₄]·8H₂O | Monoclinic | — | — |
| Jungite | Ca₂Zn₄Fe³⁺₈(PO₄)₉(OH)₉·16H₂O | Orthorhombic | 1.0 | — |
| Junitoite | CaZn₂Si₂O₇·H₂O | Orthorhombic | 4.5 | — |
| Junoite | Cu₂Pb₃Bi₈(S,Se)₁₆ | Monoclinic | — | — |
| Juonniite | — | Orthorhombic | — | — |
| Jurbanite | AlSO₄(OH)·5H₂O | Monoclinic | — | — |
| Jusite | Na₂Ca₁₅Al₄Si₁₆O₅₄·17H₂O | — | — | — |
| Juxingite | Bi₆Cu₁₄₀Fe₃₀S₁₂₅ | Cubic | — | — |
| Jáchymovite | — | Monoclinic | — | — |
| Jôkokuite | — | Triclinic | — | — |
| Jörgkellerite | — | Trigonal | — | — |
| Jørgensenite | Na₂Sr₁₄Na₂Al₁₂F₆₄(OH)₄ | Monoclinic | — | — |