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Trigonal crystal system
584 minerals
| Mineral | Chemical formula | Mohs hardness | Density |
|---|---|---|---|
| Abellaite | NaPb₂(CO₃)₂(OH) | — | — |
| Abenakiite-(Ce) | Na₂₆Ce₆(Si₆O₁₈)(PO₄)₆(CO₃)₆(SO₂)O | — | — |
| Abhurite | Sn²⁺₂₁O₆(OH)₁₄Cl₁₆ | 2.0 | — |
| Adachiite | CaFe²⁺₃Al₆(Si₅AlO₁₈)(BO₃)₃(OH)₃(OH) | 7.0 | — |
| Aerugite | Ni₈.₅(AsO₄)₂As⁵⁺O₈ | 4.0 | 5.85 g/cm³ |
| Afghanite | (Na,K)₂₂Ca₁₀(Si₂₄Al₂₄)O₉₆(SO₄)₆Cl₆ | — | — |
| Agujaite | Na₆Al₆(H₂O)₁₅(OH)₃(AsO₄)₅(AsO₃OH)₃⋅3H₂O | — | — |
| Akimotoite | MgSiO₃ | — | — |
| Aktashite | Cu₆Hg₃As₄S₁₂ | — | — |
| Alarsite | AlAsO₄ | — | 3.35 g/cm³ |
| Aleksite | PbBi₂Te₂S₂ | 2.0 | — |
| Allendeite | Sc₄Zr₃O₁₂ | — | — |
| Alloriite | (Na,K,Ca)₂₄(Na,Ca)₄Ca₄(Si,Al)₄₈O₉₆(SO₄)₄(SO₃,CO₃)₂(OH,Cl)₂(H₂O,OH)₄ | — | — |
| Alluaivite | Na₁₉(Ca,Mn²⁺)₆(Ti,Nb)₃Si₂₆O₇₄Cl·2H₂O | — | — |
| Almeidaite | PbZn₂(Mn,Y)(Ti,Fe³⁺)₁₈O₃₆(OH,O)₂ | — | — |
| Alumino-oxy-rossmanite | — | 7.0 | — |
| Aluminocerite-(CeCa) | (Ce₆Ca₃)☐Al(SiO₄)₃(SiO₃OH)₄(OH)₃ | — | — |
| Aluminocoquimbite | AlFe(SO₄)₃·9H₂O | — | — |
| Aluminopyracmonite | (NH₄)₃Al(SO₄)₃ | — | — |
| Aluminotaipingite-(CeCa) | (Ce₆Ca₃)◻Al(SiO₄)₃[SiO₃(OH)]₄F₃ | — | — |
| Alunite | KAl₃(SO₄)₂(OH)₆ | — | — |
| Amableite-(Ce) | Na₁₅[(Ce₁.₅Na₁.₅)Mn₃]Mn₂Zr₃◻Si[Si₂₄O₆₉(OH)₃](OH)₂·H₂O | — | — |
| Amakinite | Fe(OH)₂ | — | — |
| Ammonioalunite | (NH)₄Al₃(SO₄)₂(OH)₆ | — | — |
| Ammoniojarosite | (NH)₄Fe³⁺₃(SO₄)₂(OH)₆ | — | — |
| Anatolyite | Na₆(Ca,Na)(Mg,Fe³⁺)₃Al(AsO₄)₆ | — | — |
| Andersonite | Na₂Ca(UO₂)(CO₃)₃·6H₂O | 2.5 | — |
| Andrianovite | Na₁₂(K,Sr,Ce)₃Ca₆Mn₃Zr₃Nb(Si₂₅O₇₃)(O,H₂O,OH)₅ | — | — |
| Ankerite | Ca(Fe²⁺,Mg)(CO₃)₂ | — | 3.00 g/cm³ |
| Antarcticite | CaCl₂·6H₂O | — | 1.72 g/cm³ |
| Antimony (native) | Sb | 3.3 | 6.66 g/cm³ |
| Aphthitalite | K₃Na(SO₄)₂ | 3.0 | 2.75 g/cm³ |
| Aqualite | (H₃O)₈(Na,K,Sr)₅Ca₆Zr₃Si₂₆O₆₆(OH)₉Cl | — | — |
| Aradite | BaCa₆[(SiO₄)(VO₄)](VO₄)₂F | — | — |
| Aravaite | Ba₂Ca₁₈(SiO₄)₆(PO₄)₃(CO₃)F₃O | — | — |
| Arctite | Na₅Ca₇Ba(PO₄)₆F₃ | 5.0 | — |
| Argentojarosite | AgFe³⁺₃(SO₄)₂(OH)₆ | — | — |
| Argentopearceite | Ag₁₆As₂S₁₁ | — | — |
| Argentopolybasite | [Ag₉AgS₄][Ag₆Sb₂S₇] | — | — |
| Argesite | (NH₄)₇Bi₃Cl₁₆ | — | — |
| Ariegilatite | BaCa₁₂(SiO₄)₄(PO₄)₂F₂O | — | — |
| Armangite | Mn²⁺₂₆As³⁺₁₈O₅₀(CO₃)(OH)₄ | — | — |
| Arrheniusite-(Ce) | — | — | — |
| Arsenic (native) | As | 3.5 | 5.68 g/cm³ |
| Arsenobenauite | SrFe³⁺₃(AsO₄)(AsO₃OH)(OH)₆ | — | — |
| Arsenocrandallite | CaAl₃(AsO₄)(AsO₃OH)(OH)₆ | — | — |
| Arsenoflorencite-(Ce) | CeAl₃(AsO₄)₂(OH)₆ | — | — |
| Arsenoflorencite-(La) | LaAl₃(AsO₄)₂(OH)₆ | — | — |
| Arsenogorceixite | BaAl₃(AsO₄)(AsO₃OH)(OH)₆ | — | — |
| Arsenogoyazite | SrAl₃(AsO₄)(AsO₃OH)(OH)₆ | — | — |
| Asbecasite | Ca₃(Ti,Sn₄+)Be₂(AsO₃)₆(SiO₄)₂ | — | — |
| Auropearceite | [Ag₉AuS₄][Ag₆As₂S₇] | — | — |
| Auropolybasite | [Ag₉AuS₄][Ag₆Sb₂S₇] | — | — |
| Aurorite | Mn²⁺Mn⁴⁺₃O₇·3H₂O | — | — |
| Bacaferrite | BaCaFe₄O₈ | — | — |
| Backite | Pb₂AlTeO₆Cl | — | — |
| Bararite | (NH₄)₂SiF₆ | — | 2.01 g/cm³ |
| Bario-olgite | Na(Na,Sr,Ce)₂Ba(PO₄)₂ | — | — |
| Barrotite | Cu₉Al(HSiO₄)₂[(SO₄)(HAsO₄)₀.₅](OH)₁₂·8H₂O | — | — |
| Barwoodite | Mn²⁺₆Nb₅+(SiO₄)₂O₃(OH)₃ | — | — |
| Barysilite | Pb₈Mn²⁺[Si₂O₇]₃ | — | — |
| Beaverite-(Cu) | Pb(Fe³⁺₂Cu)(SO₄)₂(OH)₆ | — | — |
| Beaverite-(Zn) | Pb(Fe³⁺₂Zn)(SO₄)₂(OH)₆ | — | — |
| Bechererite | — | — | — |
| Belendorffite | Cu₇Hg₆ | — | — |
| Belomarinaite | KNa(SO₄) | — | — |
| Belovite-(Ce) | NaCeSr₃(PO₄)₃F | 5.0 | — |
| Belovite-(La) | NaLaSr₃(PO₄)₃F | 5.0 | — |
| Benstonite | — | — | — |
| Berborite | — | — | — |
| Berlinite | AlPO₄ | 6.5 | 2.65 g/cm³ |
| Berndtite | SnS₂ | — | 4.17 g/cm³ |
| Beudantite | PbFe³⁺₃(AsO₄)(SO₄)(OH)₆ | — | — |
| Biachellaite | (Na,Ca,K)₈(Si₆Al₆O₂₄)(SO₄)₂(OH)₀.₅·H₂O | — | — |
| Bismuth (native) | Bi | 2.3 | 9.77 g/cm³ |
| Bluebellite | Cu₆(IO₃)(OH)₁₀Cl | — | — |
| Bobdownsite | — | — | — |
| Bosiite | NaFe³⁺₃(Al₄Mg₂)(Si₆O₁₈)(BO₃)₃(OH)₃O | 7.0 | — |
| Botuobinskite | — | — | — |
| Brandholzite | MgSb₂(OH)₁₂·6H₂O | — | — |