| Kaatialaite | Fe(H₂AsO₄)₃ * 5H₂O | Monoclinic | — | — |
| Kadyrelite | [(Hg¹⁺)₂]₃OBr₃(OH) | Cubic | — | — |
| Kaersutite | NaCa₂(Mg₃AlTi)(Si₆Al₂)O₂₂O₂ | Monoclinic | — | — |
| Kafehydrocyanite | — | Tetragonal | — | 1.98 g/cm³ |
| Kahlenbergite | KAl₁₁O₁₇ | Hexagonal | — | — |
| Kahlerite | Fe(UO₂)₂(AsO₄)₂ * 12H₂O | — | — | — |
| Kainite | KMg(SO₄)Cl·3H₂O | Monoclinic | — | 2.10 g/cm³ |
| Kainosite-(Y) | Ca₂Y₂(SiO₃)₄(CO₃)·H₂O | — | — | — |
| Kainotropite | Cu₄Fe³⁺O₂(V₂O₇)(VO₄) | Orthorhombic | — | — |
| Kaitianite | Ti³⁺₂Ti₄+O₅ | Monoclinic | — | — |
| Kalborsite | K₆Al₄BSi₆O₂₀(OH)₄Cl | Tetragonal | — | — |
| Kalgoorlieite | As₂Te₃ | Monoclinic | — | 5.77 g/cm³ |
| Kaliborite | HKMg₂B₁₂O₁₆(OH)₁₀·4H₂O | Monoclinic | — | — |
| Kalicinite | KHCO₃ | Monoclinic | — | 2.23 g/cm³ |
| Kalifersite | (K,Na)₅Fe³⁺₇Si₂₀O₅₀(OH)₆ * 12H₂O | — | — | — |
| Kalininite | ZnCr₂S₄ | Cubic | — | 3.95 g/cm³ |
| Kalinite | KAl(SO₄)₂·11H₂O | Monoclinic | — | — |
| Kaliochalcite | KCu₂(SO₄)₂[(OH)(H₂O)] | Monoclinic | 4.0 | 3.49 g/cm³ |
| Kaliophilite | KAlSiO₄ | Hexagonal | — | 2.54 g/cm³ |
| Kalistrontite | K₂Sr(SO₄)₂ | Trigonal | — | — |
| Kalithallite | K₃Tl³⁺Cl₆*₂H₂O | Tetragonal | — | — |
| Kalsilite | KAlSiO₄ | Hexagonal | — | 2.54 g/cm³ |
| Kalungaite | PdAsSe | Cubic | — | 7.46 g/cm³ |
| Kalyuzhnyite-(Ce) | NaKCaSrCeTi(Si₈O₂₁)OF(H₂O)₃ | Monoclinic | — | — |
| Kamaishilite | Ca₂(Al₂SiO₆)(OH)₂ | Tetragonal | — | — |
| Kamarizaite | Fe³⁺₃(AsO₄)₂(OH)₃·3H₂O | Triclinic | — | — |
| Kambaldaite | NaNi₄(CO₃)₃(OH)₃ * 3H₂O | Hexagonal | — | — |
| Kamchatkite | KCu₃(SO₄)₂OCl | Orthorhombic | 3.5 | — |
| Kamenevite | K₂TiSi₃O₉*H₂O | Orthorhombic | — | — |
| Kamiokite | Fe₂Mo₃O₈ | Hexagonal | — | — |
| Kamitugaite | PbAl[(UO₂)₅(PO₄)₂.₃₈(AsO₄)₀.₆₂O₂(OH)₂] * 1₁.₅H₂O | Triclinic | — | — |
| Kamotoite-(Y) | Y₂(UO₂)₄(CO₃)₃O₄ * 14H₂O | Monoclinic | — | — |
| Kampelite | Ba₆Mg₃Sc₈(PO₄)₁₂(OH)₆*₇H₂O | Orthorhombic | — | — |
| Kampfite | Ba₁₂(Si₁₁Al₅)O₃₁(CO₃)₈Cl₅ | Monoclinic | 3.0 | — |
| Kamphaugite-(Y) | Ca(Y,REE)(CO₃)₂(OH) * H₂O | Tetragonal | — | — |
| Kanatzidisite | (SbBiS₃)₂Te₂ | Monoclinic | — | — |
| Kanemite | HNaSi₂O₅ * 3H₂O | — | — | — |
| Kangite | (Sc,Ti,Al,Zr,Mg,Ca,☐)₂O₃ | Cubic | — | — |
| Kannanite | Ca₄Al₄(AlMg)(VO₄)(SiO₄)₂(Si₃O₁₀)(OH)₆ | Orthorhombic | — | — |
| Kanoite | Mn²⁺(Mg,Mn²⁺)Si₂O₆ | Monoclinic | — | — |
| Kanonaite | Mn³⁺AlOSiO₄ | — | — | — |
| Kanonerovite | Na₃Mn²⁺(P₃O₁₀) * 12H₂O | Monoclinic | — | — |
| Kantorite | K₂NaMg(SO₄)₂F | Orthorhombic | — | — |
| Kaolinite | Al₂Si₂O₅(OH)₄ | Triclinic | 1.0 | — |
| Kapellasite | Cu₃Zn(OH)₆Cl₂ | Trigonal | — | — |
| Kapitsaite-(Y) | (Ba,K,Pb)₄(Y,Ca)₂Si₈(B,Si)₄O₂₈F | Triclinic | — | — |
| Kapundaite | CaNaFe³⁺₄(PO₄)₄(OH)₃·5H₂O | Triclinic | — | — |
| Kapustinite | Na₅(Na,Mn²⁺)<₁Zr(H₂Si₆O₁₈) | Monoclinic | — | — |
| Karasugite | SrCa[Al(F,OH)₇] | Monoclinic | — | — |
| Karchevskyite | Mg₁₈Al₉(OH)₅₄Sr₂(CO₃)₉(H₂O)₆(H₃O)₅ | Trigonal | — | — |
| Karelianite | V³⁺₂O₃ | Trigonal | — | — |
| Karenwebberite | NaFe²⁺(PO₄) | Orthorhombic | — | — |
| Karibibite | Fe³⁺₃(As³⁺O₂)₄(As³⁺₂O₅)(OH) | Orthorhombic | — | — |
| Karlite | Mg₇(BO₃)₃(OH,Cl)₅ | Orthorhombic | 5.5 | — |
| Karlleuite | Ca₂MnO₄ | Tetragonal | — | — |
| Karlseifertite | Pb(Ga₂Ge)(AsO₄)₂(OH)₆ | Trigonal | — | — |
| Karnasurtite-(Ce) | (Ce,La,Th)(Ti,Nb)(Al,Fe)(Si₂O₇)(OH)₄ * 3H₂O | Amorphous | — | — |
| Karpenkoite | Co₃(V₂O₇)(OH)₂·2H₂O | Trigonal | — | — |
| Karpinskite | (Mg,Ni)₂Si₂O₅(OH)₂ (?) | — | — | — |
| Karpovite | Tl₂VO(SO₄)₂(H₂O) | Monoclinic | — | — |
| Karupmøllerite-Ca | — | — | — | — |
| Karwowskiite | Ca₉Mg(Fe²⁺₀,₅◻₀,₅)(PO₄)₇ | Trigonal | — | 3.08 g/cm³ |
| Kasatkinite | Ba₂Ca₈B₅Si₈O₃₂(OH)₃·6H₂O | Monoclinic | — | — |
| Kashinite | (Ir,Rh)₂S₃ | — | — | — |
| Kaskasite | (Mo,Nb)S₂·(Mg₁₋ₓAlₓ)(OH)₂₊ₓ | Trigonal | — | — |
| Kasolite | Pb(UO₂)SiO₄·H₂O | Monoclinic | — | — |
| Kassite | CaTi₂O₄(OH)₂ | Monoclinic | 5.0 | 3.23 g/cm³ |
| Kastningite | (Mn²⁺,Fe²⁺,Mg)Al₂(PO₄)₂(OH)₂·8H₂O | — | — | — |
| Katanite | Ba₃NbFe₃Si₂O₁₄ | Trigonal | — | — |
| Katayamalite | KLi₃Ca₇Ti₂(SiO₃)₁₂(OH)₂ | Monoclinic | — | — |
| Katerinopoulosite | (NH₄)₂Zn(SO₄)₂*₆H₂O | Monoclinic | — | — |
| Katiarsite | KTiO(AsO₄) | Orthorhombic | — | 3.30 g/cm³ |
| Katoite | Ca₃Al₂(SiO₄)₃-x(OH)₄x (x = ₁.₅-₃) | Cubic | — | — |
| Katophorite | Na(NaCa)(Mg₄Al)(Si₇Al)O₂₂(OH)₂ | Monoclinic | — | — |
| Katoptrite | (Mn²⁺,Mg)₁₃(Al,Fe³⁺)₄Sb₅+₂(SiO₄)₂O₂₀ | — | — | — |
| Katsarosite | Zn(C₂O₄)⋅2H₂O | Monoclinic | — | — |
| Kawazulite | Bi₂Te₂Se | Trigonal | 1.5 | 7.79 g/cm³ |
| Kayrobertsonite | [MnAl₂(PO₄)₂(OH)₂(H₂O)₄]*₂H₂O | Triclinic | — | — |
| Kayupovaite | Na₂Mn₁₀[(Si₁₄Al₂)O₃₈(OH)₈]·₇H₂O | Monoclinic | — | — |
| Kazakhstanite | Fe³⁺₅V₄+₃V₅+₁₂O₃₉(OH)₉ * 9H₂O | — | — | — |
| Kazakovite | Na₆Mn²⁺Ti(Si₆O₁₈) | Trigonal | — | — |
| Kazanskyite | Ba☐TiNbNa₃Ti(Si₂O₇)₂O₂(OH)₂(H₂O)₂ | Triclinic | — | — |
| Kaznakhtite | — | Trigonal | — | — |
| Kaňkite | — | — | — | — |
| Keatite | SiO₂ | Tetragonal | — | 2.63 g/cm³ |
| Keckite | CaMn(Fe³⁺,Mn)₂Fe³⁺₂(PO₄)₄(OH)₃(H₂O)₇ | Monoclinic | — | — |
| Kegelite | Pb₄Al₂Si₄O₁₀(SO₄)(CO₃)₂(OH)₄ | — | — | — |
| Kegginite | Pb₃Ca₃[AsV₁₂O₄₀(VO)]*₂₀H₂O | Trigonal | — | — |
| Keilite | FeS | Cubic | 4.0 | 4.29 g/cm³ |
| Keithconnite | Pd₂₀Te₇ | Trigonal | — | 10.79 g/cm³ |
| Keiviite-(Y) | Y₂Si₂O₇ | Monoclinic | — | 4.26 g/cm³ |
| Keiviite-(Yb) | Yb₂Si₂O₇ | Monoclinic | — | 6.24 g/cm³ |
| Keldyshite | (Na,H)₂ZrSi₂O₇ | Triclinic | — | — |
| Kellyite | Mn²⁺₂Al(AlSiO₅)(OH)₄ | — | — | — |
| Kelyanite | (Hg+₂)₆Sb³⁺BrCl₂O₆ | Monoclinic | — | — |
| Kemmlitzite | SrAl₃(AsO₄)(SO₄)(OH)₆ | — | 5.5 | — |
| Kempite | Mn²⁺₂Cl(OH)₃ | — | — | — |
| Kenhsuite | Hg²⁺₃S₂Cl₂ | Orthorhombic | — | — |
| Kenngottite | Mn²⁺₃Fe³⁺₄(PO₄)₄(OH)₆(H₂O)₂ | Monoclinic | — | — |
| Kenoargentotennantite-(Fe) | — | Cubic | — | — |
| Kenoargentotetrahedrite-(Fe) | Ag₆(Cu₄Fe₂)Sb₄S₁₂☐ | — | — | — |
| Kenoargentotetrahedrite-(Zn) | [Ag₆]⁴⁺(Cu₄Zn₂)Sb₄S₁₂◻ | Cubic | — | — |
| Kenomicrolite | ◻₂Ta₂[O₄(OH)₂]◻ | Cubic | — | — |
| Kenoplumbomicrolite | (Pb,☐)₂Ta₂O₆(☐,OH,O) | Cubic | — | — |
| Kenotobermorite | Ca₄Si₆O₁₅(OH)₂(H₂O)₂·3H₂O | — | — | — |
| Kentbrooksite | (Na,REE)₁₅(Ca,REE)₆(Mn²⁺,Fe²⁺)₃Zr₃Nb[Si₂₅O₇₄]F₂ * 2H₂O | Trigonal | — | — |
| Kentrolite | Pb₂Mn³⁺₂(Si₂O₇)O₂ | Orthorhombic | — | — |
| Kenyaite | Na₂Si₂₂O₄₁(OH)₈ * 6H₂O | Monoclinic | — | — |
| Keplerite | — | Trigonal | — | — |
| Kerimasite | Ca₃Zr₂(SiFe³⁺₂)O₁₂ | Cubic | 7.0 | — |
| Kermesite | Sb₂OS₂ | Triclinic | — | 4.68 g/cm³ |
| Kernite | Na₂B₄O₆(OH)₂·3H₂O | Monoclinic | — | — |
| Kernowite | — | Monoclinic | — | — |
| Kesebolite-(Ce) | — | Monoclinic | — | — |
| Kettnerite | CaBiCO₃OF | Orthorhombic | — | — |
| Keutschite | Cu₂AgAsS₄ | Tetragonal | — | — |
| Keyite | Cu²⁺₃Zn₄Cd₂(AsO₄)₆ * 2H₂O | — | — | — |
| Keystoneite | Mg₀.₅NiFe³⁺(Te⁴⁺O₃)₃·4.5H₂O | — | — | — |
| Khademite | AlSO₄F·5H₂O | — | — | — |
| Khaidarkanite | Cu₄Al₃(OH)₁₄F₃·2H₂O | Monoclinic | — | — |
| Khamrabaevite | TiC | Cubic | 9.0 | 4.89 g/cm³ |
| Khanneshite | (Na,Ca)₃(Ba,Sr,Ce,Ca)₃(CO₃)₅ | Hexagonal | — | — |
| Kharaelakhite | (Cu,Pt,Pb,Fe,Ni)₉S₈ | Orthorhombic | — | — |
| Khatyrkite | (Cu,Zn)Al₂ | Tetragonal | — | — |
| Khesinite | Ca₄(Mg₃Fe³⁺₉)O₄(Fe³⁺₉Si₃)O₃₆ | Triclinic | — | — |
| Khibinskite | K₂ZrSi₂O₇ | Monoclinic | — | 3.19 g/cm³ |
| Khinite | Pb²⁺Cu²⁺₃[Te₆+O₆](OH)₂ | Orthorhombic | — | — |
| Khmaralite | (Mg,Al,Fe)₁₆[(Al,Si,Be)₁₂O₃₆]O₄ | — | — | — |
| Khomyakovite | Na₁₂Sr₃Ca₆Fe₃Zr₃W[Si₂₅O₇₃](O,OH,H₂O)₃(OH,Cl)₂ | Trigonal | — | — |
| Khorixasite | (Bi₀.₆₇☐₀.₃₃)Cu(VO₄)(OH) | Monoclinic | — | — |
| Khrenovite | Na₃Fe³⁺₂(AsO₄)₃ | Monoclinic | — | — |
| Khristovite-(Ce) | {CaCe}{MgAlMn²⁺}(Si₂O₇)(SiO₄)(OH)F | Monoclinic | — | — |
| Khurayyimite | Ca₇Zn₄(Si₂O₇)₂(OH)₁₀*₄H₂O | Monoclinic | — | — |
| Khvorovite | (Pb,Ba,K)₄Ca₂[Si₈B₂(Si,B)₂O₂₈]F | Triclinic | — | — |
| Kiddcreekite | Cu₆WSnS₈ | — | 4.0 | 4.88 g/cm³ |
| Kidodite | BaMg₂Fe₁₆O₂₇ | Hexagonal | — | — |
| Kidwellite | NaFe³⁺₉₊ₓ(PO₄)₆(OH)₁₁·3H₂O (x ≈ 0.33) | Monoclinic | 3.0 | 3.34 g/cm³ |
| Kieftite | CoSb₃ | Cubic | — | 7.59 g/cm³ |
| Kieserite | Mg(SO₄)(H₂O) | Monoclinic | 3.5 | — |
| Kihlmanite-(Ce) | Ce₂TiO₂(SiO₄)(HCO₃)₂(H₂O) | Triclinic | — | — |
| Kilchoanite | Ca₆(SiO₄)(Si₃O₁₀) | Orthorhombic | — | — |
| Killalaite | Ca₆.₄(H₀.₆Si₂O₇)₂(OH)₂ | Monoclinic | — | — |
| Kimrobinsonite | (Ta,Nb)(OH)₅-₂x(O,CO₃)x ; x near ₁.₂ | — | — | — |
| Kimuraite-(Y) | CaY₂(CO₃)₄·6H₂O | Orthorhombic | — | — |
| Kimzeyite | Ca₃(Zr,Ti)₂((Si,Al,Fe³⁺)O₄)₃ | Cubic | 7.0 | — |
| Kingite | Al₃(PO₄)₂F₂(OH) · 7H₂O | Triclinic | — | — |
| Kingsgateite | — | Tetragonal | — | — |
| Kingsmountite | Ca₄(Fe²⁺,Mn²⁺)Al₄(PO₄)₆(OH)₄ * 12H₂O | Triclinic | — | — |
| Kingstonite | (Rh,Ir,Pt)₃S₄ | Monoclinic | 6.0 | — |
| Kinichilite | Mg₀.₅Mn²⁺Fe³⁺(Te⁴⁺O₃)₃·4.5H₂O | — | — | — |
| Kinoite | Ca₂Cu₂Si₃O₁₀·2H₂O | Monoclinic | 2.5 | — |
| Kinoshitalite | (Ba,K)(Mg,Mn²⁺,Al)₃(Al₂Si₂O₁₀)(OH)₂ | — | — | — |
| Kintoreite | PbFe₃(PO₄)(PO₃OH)(OH)₆ | Trigonal | — | — |
| Kipushite | (Cu,Zn)₅Zn(PO₄)₂(OH)₆ * H₂O | Monoclinic | — | — |
| Kircherite | [Na₅Ca₂K](Si₆Al₆O₂₄)(SO₄)₂·0.33H₂O | Trigonal | — | — |
| Kirchhoffite | CsBSi₂O₆ | Tetragonal | — | 3.46 g/cm³ |
| Kirkiite | Pb₁₀Bi₃As₃S₁₉ | — | — | — |
| Kirschsteinite | CaFe²⁺SiO₄ | Orthorhombic | — | — |
| Kiryuite | NaMnAl(PO₄)F₃ | Monoclinic | — | — |
| Kishonite | — | Cubic | — | — |
| Kitagohaite | Pt₇Cu | Cubic | — | 19.91 g/cm³ |
| Kitkaite | NiTeSe | — | 3.0 | — |
| Kittatinnyite | Ca₂Mn₂Mn(SiO₄)₂(OH)₄ * 9H₂O | — | — | — |
| Kladnoite | C₆H₄(CO)₂NH | Monoclinic | — | — |
| Klajite | MnCu₄(AsO₄)₂(AsO₃OH)₂·9H₂O | Triclinic | — | — |
| Klaprothite | Na₆(UO₂)(SO₄)₄·4H₂O | Monoclinic | — | — |
| Klebelsbergite | Sb₄O₄(SO₄)(OH)₂ | Orthorhombic | — | 4.42 g/cm³ |
| Kleberite | FeTi₈O₁₁(OH)₅ | Monoclinic | — | — |
| Kleemanite | ZnAl₂(PO₄)₂(OH)₂·3H₂O | Monoclinic | — | — |
| Kleinite | (Hg₂N)(Cl,SO₄)·nH₂O | Hexagonal | — | — |
| Klockmannite | CuSe | Hexagonal | — | 6.04 g/cm³ |
| Klyuchevskite | K₃Cu₃(Fe³⁺,Al)(SO₄)₄O₂ | Monoclinic | — | — |
| Klöchite | (Fe²⁺Fe³⁺)☐₂KZn₃(Si₁₂O₃₀) | Hexagonal | — | — |
| Knasibfite | K₃Na₄(SiF₆)₃(BF₄) | Orthorhombic | — | — |
| Knorringite | Mg₃Cr₂(SiO₄)₃ | Cubic | — | — |
| Koashvite | Na₆(Ca,Mn)(Ti,Fe)Si₆O₁₈ * H₂O | Orthorhombic | — | — |
| Kobeite-(Y) | (REE,Fe,U)₃ Zr(Ti,Nb)₃ O₁₂ | — | — | — |
| Kobellite | Pb₁₁(Cu,Fe)₂(Bi,Sb)₁₅S₃₅ | Orthorhombic | — | — |
| Kobokoboite | Al₆(PO₄)₄(OH)₆·11H₂O | Triclinic | — | — |
| Kobyashevite | Cu₅(SO₄)₂(OH)₆·4H₂O | Triclinic | — | — |
| Kochite | Ca₂MnZrNa₃Ti(Si₂O₇)₂(OF)F₂ | Triclinic | — | — |
| Kochkarite | PbBi₄Te₇ | — | — | — |
| Kochsándorite | — | Orthorhombic | — | — |
| Kodamaite | Na₃(Ca₅Na)Si₁₆O₃₆(OH)₄F₂·(14-x)H₂O | Triclinic | — | — |
| Koechlinite | Bi₂MoO₆ | Orthorhombic | — | 8.14 g/cm³ |
| Koenenite | Na₄Mg₉Al₄Cl₁₂(OH)₂₂ | Trigonal | — | — |
| Kogarkoite | Na₃SO₄F | Monoclinic | 3.5 | 2.58 g/cm³ |
| Kojonenite | Pd₇₋ₓSnTe₂ (0.3≤x≤0.8) | Tetragonal | — | — |
| Kokchetavite | K(AlSi₃O₈) | Hexagonal | — | 2.46 g/cm³ |
| Kokinosite | Na₂Ca₂(V₁₀O₂₈)·24H₂O | Triclinic | — | — |
| Koksharovite | CaMg₂Fe³⁺₄(VO₄)₆ | Triclinic | 4.5 | — |
| Koktaite | (NH₄)₂Ca(SO₄)₂ * H₂O | Monoclinic | — | — |
| Kolarite | PbTeCl₂ | Orthorhombic | — | — |
| Kolbeckite | ScPO₄·2H₂O | Monoclinic | — | — |
| Kolfanite | Ca₂Fe³⁺₃O₂(AsO₄)₃·2H₂O | Monoclinic | — | — |
| Kolicite | Mn²⁺₇Zn₄(AsO₄)₂(SiO₄)₂(OH)₈ | — | — | — |
| Kolitschite | Pb[Zn₀.₅,☐₀.₅]Fe₃(AsO₄)₂(OH)₆ | Monoclinic | — | — |
| Kollerite | (NH₄)₂Fe³⁺(SO₃)₂(OH)*H₂O | Orthorhombic | — | — |
| Kolovratite | NixZny(VO₄)₀.₆₇(x+y) * nH₂O | — | — | — |
| Kolskyite | (Ca,☐)Ti₂Na₂Ti₂(Si₂O₇)₂O₄(H₂O)₇ | Triclinic | — | — |
| Kolwezite | CuCo(CO₃)(OH)₂ | Triclinic | — | — |
| Kolymite | Cu₇Hg₆ | Cubic | 4.0 | 13.10 g/cm³ |
| Komarovite | (Ca,Mn)Nb₂[O₃|Si₂O₇] * 3.₅H₂O | — | — | — |
| Kombatite | Pb₁₄(VO₄)₂O₉Cl₄ | Monoclinic | — | — |
| Komkovite | BaZr[Si₃O₉] * 3H₂O | — | — | — |
| Konderite | Cu₃Pb(Rh,Pt,Ir)₈S₁₆ | — | — | — |
| Koninckite | Fe³⁺PO₄ * 3H₂O | Tetragonal | — | — |
| Kononovite | NaMg(SO₄)F | Monoclinic | — | 2.80 g/cm³ |
| Konyaite | Na₂Mg(SO₄)₂ * 5H₂O | — | — | — |
| Konzettite | CaMn⁴⁺Te₆⁺O₆ | Trigonal | — | — |
| Kopernikite | K(Ti₇Cr³⁺)O₁₆ | Tetragonal | — | — |
| Kopylovite | K₂Ti(Si₃O₉) | Hexagonal | — | — |
| Koragoite | (Mn²⁺,Fe³⁺)₃(Nb,Ta,Ti)₂(Nb,Mn)₂(W,Ta)₂O₂₀ | Monoclinic | — | — |
| Koritnigite | Zn(AsO₃OH)·H₂O | — | — | — |
| Kornelite | Fe₂(SO₄)₃ * 7H₂O | Monoclinic | — | — |
| Kornerupine | Mg₃Al₆(Si,Al,B)₅O₂₁(OH) | Orthorhombic | — | — |
| Korobitsynite | (Na,☐)₄Ti₂(Si₄O₁₂)(O,OH)₂·4H₂O | — | — | — |
| Korshunovskite | Mg₂Cl(OH)₃·4H₂O | Triclinic | — | — |
| Koryakite | NaKMg₂Al₂(SO₄)₆ | Trigonal | — | — |
| Korzhinskite | Ca(B₂O₄) * H₂O | Monoclinic | — | — |
| Kosmochlor | NaCrSi₂O₆ | Monoclinic | 6.0 | 3.60 g/cm³ |
| Kosnarite | KZr₂(PO₄)₃ | Trigonal | 4.5 | 3.06 g/cm³ |
| Kostovite | AuCuTe₄ | — | — | — |
| Kostylevite | K₂Zr(Si₃O₉) * H₂O | Monoclinic | — | — |
| Kotoite | Mg₃(BO₃)₂ | Orthorhombic | 6.5 | 3.11 g/cm³ |
| Kottenheimite | Ca₃Si(SO₄)₂(OH)₆·12H₂O | Hexagonal | — | — |
| Kotulskite | Pd(Te,Bi) | — | — | — |
| Koutekite | Cu₅As₂ | Hexagonal | — | — |
| Kovdorskite | Mg₂PO₄(OH)·3H₂O | — | — | — |
| Kozoite-(La) | (La,Nd)(CO₃)(OH) | Orthorhombic | — | — |
| Kozoite-(Nd) | (Nd,La,Sm,Pr)(CO₃)(OH) | Orthorhombic | — | — |
| Kozyrevskite | Cu₄O(AsO₄)₂ | Orthorhombic | — | — |
| Kraisslite | Zn₃(Mn,Mg)₂₅(Fe³⁺,Al)(As³⁺O₃)₂[(Si,As₅+)O₄]₁₀(OH)₁₆ | — | — | — |
| Krasheninnikovite | KNa₂CaMg(SO₄)₃F | Hexagonal | — | — |
| Krasnoshteinite | Al₈[B₂O₄(OH)₂](OH)₁₆Cl₄*₇H₂O | — | — | — |
| Krasnovite | Ba(Al,Mg)(PO₄,CO₃)(OH)₂ * H₂O | Orthorhombic | — | — |
| Kratochvílite | C₁₃H₁₀ | Orthorhombic | — | — |
| Krausite | KFe(SO₄)₂ * H₂O | Monoclinic | — | — |
| Krauskopfite | BaSi₂O₅ * 3H₂O | — | — | — |
| Krautite | Mn(AsO₃OH)·H₂O | — | — | — |
| Kravtsovite | PdAg₂S | Orthorhombic | — | — |
| Kreiterite | CsLi₂Fe³⁺(Si₄O₁₀)F₂ | Monoclinic | — | — |
| Kremersite | (NH₄)₂Fe³⁺Cl₅·H₂O | — | — | — |
| Krennerite | Au₃AgTe₈ | Orthorhombic | — | — |
| Krettnichite | PbMn³⁺₂(VO₄)₂(OH)₂ | Monoclinic | — | — |
| Kribergite | Al₅(PO₄)₃(SO₄)(OH)₄ * 4H₂O | Triclinic | — | — |
| Krieselite | Al₂(GeO₄)F₂ | Orthorhombic | — | 4.02 g/cm³ |
| Krinovite | Na₂Mg₄Cr³⁺₂(Si₆O₁₈)O₂ | — | — | — |
| Kristekite | Cu₂(H₂O)₄(UO₂)(SeO₃)₃·4H₂O | Monoclinic | — | — |
| Kristiansenite | Ca₂ScSn(Si₂O₇)(Si₂O₆OH) | Triclinic | — | — |
| Kristjánite | KNa₂H(SO₄)₂ | Monoclinic | — | — |
| Krivovichevite | Pb₃Al(OH)₆SO₄(OH) | Trigonal | 3.0 | — |
| Krotite | CaAl₂O₄ | Monoclinic | 6.5 | — |
| Kroupaite | KPb₀.₅[(UO₂)₈O₄(OH)₁₀]*₁₀H₂O | Orthorhombic | — | — |
| Kruijenite | Ca₄Al₄(SO₄)F₂(OH)₁₆*₂H₂O | Tetragonal | 3.0 | — |
| Krupičkaite | — | Monoclinic | — | — |
| Krupkaite | PbCuBi₃S₆ | Orthorhombic | 4.0 | — |
| Krut'aite | CuSe₂ | Orthorhombic | 4.0 | 6.28 g/cm³ |
| Krutovite | NiAs₂ | Cubic | 5.5 | 7.11 g/cm³ |
| Kryachkoite | (Al,Cu)₆(Fe,Cu) | Orthorhombic | — | — |
| Kryzaite | Na₄(MgCr)(PO₄)₃ | Trigonal | — | — |
| Kryzhanovskite | (Fe³⁺,Mn²⁺)₃(PO₄)₂(OH,H₂O)₃ | — | — | — |
| Králíkite | BaCl₂·2H₂O | Monoclinic | — | — |
| Krásnoite | Ca₃Al₇.₇Si₃P₄O₂₂.₉(OH)₁₃.₃F₂·8H₂O | Trigonal | — | — |
| Kröhnkite | Na₂Cu(SO₄)₂·2H₂O | Monoclinic | — | — |
| Ktenasite | (Cu,Zn)₅(SO₄)₂(OH)₆·6H₂O | Monoclinic | — | — |
| Kuannersuite-(Ce) | NaCeBa₃(PO₄)₃F₀.₅Cl₀.₅ | — | — | — |
| Kudriavite | (Cd,Pb)Bi₂S₄ | Monoclinic | — | — |
| Kudryavtsevaite | Na₃MgFe³⁺Ti₄O₁₂ | Orthorhombic | — | — |
| Kufahrite | PtPb | Hexagonal | — | 14.91 g/cm³ |
| Kukharenkoite-(Ce) | Ba₂Ce(CO₃)₃F | Monoclinic | — | 4.54 g/cm³ |
| Kukharenkoite-(La) | Ba₂(La,Ce,Th)(CO₃)₃F | Monoclinic | — | — |
| Kukisvumite | Na₆ZnTi₄(Si₈O₂₄)O₄ * 4H₂O | — | — | — |
| Kuksite | Pb₃Zn₃(PO₄)₂(TeO₆) | Trigonal | — | 6.16 g/cm³ |
| Kulanite | Ba(Fe²⁺,Mn²⁺,Mg)₂(Al,Fe³⁺)₂(PO₄)₃(OH)₃ | Monoclinic | — | — |
| Kuliginite | Fe₃Mg(OH)₆Cl₂ | Trigonal | — | — |
| Kuliokite-(Y) | Y₄Al(SiO₄)₂(OH)₂F₅ | Triclinic | — | — |
| Kulkeite | Mg₈Al(AlSi₇O₂₀)(OH)₁₀ | — | — | — |
| Kullerudite | NiSe₂ | Cubic | — | 6.57 g/cm³ |
| Kumdykolite | Na(AlSi₃O₈) | Orthorhombic | — | 2.64 g/cm³ |
| Kummerite | Mn²⁺Fe³⁺Al(PO₄)₂(OH)₂·8H₂O | Triclinic | — | — |
| Kumtyubeite | Ca₅(SiO₄)₂F₂ | Monoclinic | — | — |
| Kunatite | CuFe³⁺₂(PO₄)₂(OH)₂·4H₂O | Monoclinic | — | — |
| Kupletskite | (K,Na)₃(Mn,Fe)₇Ti₂Si₈O₂₆(OH)₄F | — | — | — |
| Kupletskite-(Cs) | Cs₂NaMn²⁺₇Ti₂(Si₄O₁₂)₂O₂(OH)₄F | — | — | — |
| Kupčíkite | Cu₃.₄Fe₀.₆Bi₅S₁₀ | Monoclinic | — | — |
| Kuramite | Cu₃SnS₄ | — | 4.5 | — |
| Kuranakhite | PbMn⁴⁺Te⁶⁺O₆ | Orthorhombic | — | — |
| Kuratite | Ca₂(Fe²⁺₅Ti)O₂[Si₄Al₂O₁₈] | Triclinic | — | — |
| Kurchatovite | Ca(Mg,Mn²⁺)[B₂O₅] | Orthorhombic | — | — |
| Kurgantaite | CaSr[B₅O₉]Cl·H₂O | Triclinic | — | — |
| Kurilite | Ag₈Te₃Se | Trigonal | — | — |
| Kurnakovite | Mg[B₃O₃(OH)₅](H₂O)₄·H₂O | Triclinic | — | — |
| Kurumsakite | Zn₈Al₈V⁵⁺₂Si₅O₃₅·27H₂O (?) | — | — | — |
| Kusachiite | Cu²⁺Bi³⁺₂O₄ | Tetragonal | — | — |
| Kushiroite | CaAlAlSiO₆ | Monoclinic | — | — |
| Kutinaite | Ag₆Cu₁₄As₇ | Cubic | 4.5 | 8.39 g/cm³ |
| Kutnohorite | CaMn²⁺(CO₃)₂ | Trigonal | — | — |
| Kuvaevite | Ir₅Ni10S16 | Trigonal | — | — |
| Kuzelite | Ca₄Al₂(OH)₁₂[SO₄] * 6H₂O | — | — | — |
| Kuzmenkoite-Mn | K₂MnTi₄(Si₄O₁₂)₂(OH)₄·5-6H₂O | — | — | — |
| Kuzmenkoite-Zn | K₂ZnTi₄(Si₄O₁₂)₂(OH)₄·6-8H₂O | — | — | — |
| Kuzminite | HgBr | Tetragonal | 1.5 | — |
| Kuznetsovite | (Hg+₂)Hg²⁺(AsO₄)Cl | Cubic | — | — |
| Kvanefjeldite | Na₄(Ca,Mn)(Si₃O₇)₂(OH)₂ | Orthorhombic | — | — |
| Kvačekite | NiSbSe | Cubic | — | 7.59 g/cm³ |
| Kyanite | Al₂OSiO₄ | Triclinic | 7.5 | 3.68 g/cm³ |
| Kyanoxalite | Na₇(Al₅-₆Si₆-₇O₂₄)(C₂O₄)₀.₅-₁.₀·5H₂O | Hexagonal | — | — |
| Kyawthuite | Bi³⁺Sb₅+O₄ | Monoclinic | — | — |
| Kyrgyzstanite | ZnAl₄(SO₄)(OH)₁₂*₃H₂O | Monoclinic | — | — |
| Kyzylkumite | V³⁺Ti₂O₅(OH) | Monoclinic | — | — |
| Kësterite | Cu₂ZnSnS₄ | Tetragonal | 4.5 | 4.61 g/cm³ |
| Köttigite | Zn₃(AsO₄)₂·8H₂O | — | — | — |