Silicate mineral

{{Short description|Rock-forming minerals with predominantly silicate anions}} {{Use dmy dates|date=February 2019}} [[File:Spodumene-sd305c.jpg|thumb|right|Lithium aluminium silicate mineral spodumene]]

'''Silicate minerals''' are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust.<ref>{{cite web|url=https://www.britannica.com/science/mineral-chemical-compound/Silicates|title=Mineral - Silicates|website=britannica.com|access-date=8 May 2018|url-status=live|archive-url=https://web.archive.org/web/20171025133427/https://www.britannica.com/science/mineral-chemical-compound/Silicates|archive-date=25 October 2017}}</ref><ref name=deer>{{Cite book| last = Deer| first = W.A.|author2=Howie, R.A.|author3=Zussman, J. | year = 1992| title = An introduction to the rock-forming minerals| publisher = Longman| location = London| edition = 2nd| isbn = 0-582-30094-0}}</ref><ref name=hurlbut>{{Cite book| last = Hurlbut| first = Cornelius S.| author2 = Klein, Cornelis| year = 1985| title = Manual of Mineralogy| edition = 20th| publisher = Wiley| isbn = 0-47180580-7| url = https://archive.org/details/manualofmineralo00klei}}</ref>

In mineralogy, the crystalline forms of silica ({{chem2|SiO2}}) are usually considered to be tectosilicates, and they are classified as such in the Dana system (75.1). However, the Nickel-Strunz system classifies them as oxide minerals (4.DA). Silica is found in nature as the mineral quartz and its polymorphs.

On Earth, a wide variety of silicate minerals occur in an even wider range of combinations as a result of the processes that have been forming and re-working the crust for billions of years. These processes include partial melting, crystallization, fractionation, metamorphism, weathering, and diagenesis.

thumb|right|Diatomaceous earth, a biogenic form of silica as viewed under a microscope. The imaged region measures approximately 1.13 by 0.69 mm. Living organisms also contribute to this geologic cycle. For example, a type of plankton known as diatoms construct their exoskeletons ("frustules") from silica extracted from seawater. The frustules of dead diatoms are a major constituent of deep ocean sediment, and of diatomaceous earth.{{Citation needed|date=April 2019}}

==General structure== A silicate mineral is generally an inorganic compound consisting of subunits with the formula [SiO_2+''n'']^2''n''−. Although depicted as such, the description of silicates as anions is a simplification. Balancing the charges of the silicate anions are metal cations, M^''x''+. Typical cations are Mg²⁺, Fe²⁺, and Na⁺. The Si-O-M linkage between the silicates and the metals are strong, polar-covalent bonds. Silicate anions ([SiO_2+''n'']^2''n''−) are invariably colorless, or when crushed to a fine powder, white. The colors of silicate minerals arise from the metal component, commonly iron.

In most silicate minerals, silicon is tetrahedral, being surrounded by four oxides. The coordination number of the oxides is variable except when it bridges two silicon centers, in which case the oxide has a coordination number of two.

Some silicon centers may be replaced by atoms of other elements, still bound to the four corner oxygen corners. If the substituted atom is not normally tetravalent, it usually contributes extra charge to the anion, which then requires extra cations. For example, in the mineral orthoclase {{chem|[KAlSi|3|O|8|]|''n''}}, the anion is a tridimensional network of tetrahedra in which all oxygen corners are shared. If all tetrahedra had silicon centers, the anion would be just neutral silica {{chem|[SiO|2|]|''n''}}. Replacement of one in every four silicon atoms by an aluminum atom results in the anion {{chem|[AlSi|3|O|8|−|]|''n''}}, whose charge is neutralized by the potassium cations {{chem|K|+}}.

==Main groups== In mineralogy, silicate minerals are classified into seven major groups according to the structure of their silicate anion:<ref>Deer, W.A.; Howie, R.A., & Zussman, J. (1992). ''An introduction to the rock forming minerals'' (2nd edition ed.). London: Longman {{ISBN|0-582-30094-0}}</ref><ref>Hurlbut, Cornelius S.; Klein, Cornelis ||1985). ''Manual of Mineralogy'', Wiley, (20th edition ed.). {{ISBN|0-471-80580-7}}</ref> {| class=wikitable ! Major group !! Structure !! Chemical formula !! Example |- | Nesosilicates ||isolated silicon tetrahedra || [SiO₄]⁴⁻ || olivine, garnet, zircon... |- | Sorosilicates ||double tetrahedra || [Si₂O₇]⁶⁻ || epidote, melilite group |- | Cyclosilicates ||rings || [Si_''n''O_3''n'']^2''n''− || beryl group, tourmaline group |- | Inosilicates ||single chain || [Si_''n''O_3''n'']^2''n''− || pyroxene group |- | Inosilicates ||double chain || [Si_4''n''O_11''n'']^6''n''− || amphibole group |- | Phyllosilicates ||sheets || [Si_2''n''O_5''n'']^2''n''− || micas and clays |- | Tectosilicates ||3D framework || [Al_''x''Si_''y''O_{(2''x''+2''y'')}]^''x''− || quartz, feldspars, zeolites |} Tectosilicates can only have additional cations if some of the silicon is replaced by an atom of lower valence such as aluminum. Al for Si substitution is common.

==Nesosilicates or orthosilicates== thumb|Orthosilicate anion {{chem|SiO|4|4-}}. The grey ball represents the silicon atom, and the red balls are the oxygen atoms. thumb|Nesosilicate specimens at the Museum of Geology in South Dakota {{main category|Nesosilicates}} Nesosilicates (from Greek {{wikt-lang|grc|νῆσος}} {{Transliteration|grc|nēsos}} 'island'), or orthosilicates, have the orthosilicate ion, present as isolated (insular) {{chem2|[SiO4](4−)}} tetrahedra connected only by interstitial cations. The Nickel–Strunz classification is 09.A –examples include:

*Phenakite group **Phenakite – {{chem2|Be2SiO4}} **Willemite – {{chem2|Zn2SiO4}} *Olivine group **Forsterite – {{chem2|Mg2SiO4}} **Fayalite – {{chem2|Fe2SiO4}} **Tephroite – {{chem2|Mn2SiO4}} *Garnet group **Pyrope – {{chem2|Mg3Al2(SiO4)3}} **Almandine – {{chem2|Fe3Al2(SiO4)3}} **Spessartine – {{chem2|Mn3Al2(SiO4)3}} **Grossular – {{chem2|Ca3Al2(SiO4)3}} **Andradite – {{chem2|Ca3Fe2(SiO4)3}} **Uvarovite – {{chem2|Ca3Cr2(SiO4)3}} **Hydrogrossular – {{chem|Ca|3|Al|2|Si|2|O|8|(SiO|4|)|3−''m''|(OH)|4''m''|}} *Zircon group **Zircon – {{chem2|ZrSiO4}} **Thorite – {{chem2|(Th,U)SiO4}} **Hafnon – {{chem2|(Hf,Zr)SiO4}} [[Image:Kyanite crystals.jpg|thumb|Kyanite crystals (unknown scale)]] *{{chem2|Al2SiO5}} group **Andalusite – {{chem2|Al2SiO5}} **Kyanite – {{chem2|Al2SiO5}} **Sillimanite – {{chem2|Al2SiO5}} **Dumortierite – {{chem|Al|6.5–7|BO|3|(SiO|4|)|3|(O,OH)|3}} **Topaz – {{chem2|Al2SiO4(F,OH)2}} **Staurolite – {{chem2|Fe2Al9(SiO4)4(O,OH)2}} *Humite group – {{chem2|(Mg,Fe)7(SiO4)3(F,OH)2}} **Norbergite – {{chem2|Mg3(SiO4)(F,OH)2}} **Chondrodite – {{chem2|Mg5(SiO4)2(F,OH)2}} **Humite – {{chem2|Mg7(SiO4)3(F,OH)2}} **Clinohumite – {{chem2|Mg9(SiO4)4(F,OH)2}} *Datolite – {{chem2|CaBSiO4(OH)}} *Titanite – {{chem2|CaTiSiO5}} *Chloritoid – {{chem2|(Fe,Mg,Mn)2Al4Si2O10(OH)4}} *Mullite (aka Porcelainite) – {{chem2|Al6Si2O13}}

==Sorosilicates== thumb|Pyrosilicate anion {{chem|Si|2|O|7|6-}} thumb|Sorosilicate exhibit at Museum of Geology in South Dakota {{main category|Sorosilicates}} Sorosilicates (from Greek {{wikt-lang|grc|σωρός}} {{Transliteration|grc|sōros}} 'heap, mound') have isolated pyrosilicate anions {{chem|Si|2|O|7|6-}}, consisting of double tetrahedra with a shared oxygen vertex—a silicon:oxygen ratio of 2:7. The Nickel–Strunz classification is 09.B. Examples include:

*Thortveitite – {{chem2|(Sc,Y)2(Si2O7)}} *Hemimorphite (calamine) – {{chem2|Zn4(Si2O7)(OH)2*H2O}} *Lawsonite – {{chem2|CaAl2(Si2O7)(OH)2*H2O}} *Axinite – {{chem2|(Ca,Fe,Mn)3Al2(BO3)(Si4O12)(OH)}} *Ilvaite – {{chem2|CaFe^{II}2Fe^{III}O(Si2O7)(OH)}} *Epidote group (has both {{chem2|(SiO4)(4−)}} and {{chem2|(Si2O7)(6−)}} groups} **Epidote – {{chem2|Ca2(Al,Fe)3O(SiO4)(Si2O7)(OH)}} **Zoisite – {{chem2|Ca2Al3O(SiO4)(Si2O7)(OH)}} ***Tanzanite – {{chem2|Ca2Al3O(SiO4)(Si2O7)(OH)}} **Clinozoisite – {{chem2|Ca2Al3O(SiO4)(Si2O7)(OH)}} **Allanite – {{chem2|Ca(Ce,La,Y,Ca)Al2(Fe^{II},Fe^{III})O(SiO4)(Si2O7)(OH)}} **Dollaseite-(Ce) – {{chem2|CaCeMg2AlSi3O11F(OH)}} *Vesuvianite (idocrase) – {{chem2|Ca10(Mg,Fe)2Al4(SiO4)5(Si2O7)2(OH)4}}

==Cyclosilicates== <!-- This section is linked from Beryl --> {{main category|Cyclosilicates}} thumb|Cyclosilicate specimens at the Museum of Geology, South Dakota [[File:Pezzottaite-256889.jpg|thumb|Pezzottaite]] [[File:Bazzite - Fibbia Ticino Switzerland.jpg|thumb|Bazzite]]

Cyclosilicates (from Greek {{wikt-lang|grc|κύκλος}} {{Transliteration|grc|kýklos}} 'circle'), or ring silicates, have three or more tetrahedra linked in a ring. The general formula is (Si_''x''O_3''x'')^2''x''−, where one or more silicon atoms can be replaced by other 4-coordinated atom(s). The silicon:oxygen ratio is 1:3. Double rings have the formula (Si_2''x''O_5''x'')^2''x''− or a 2:5 ratio. The Nickel–Strunz classification is 09.C. Possible ring sizes include:

<gallery> File:Beryll.ring.combined.png|6 units {{chem2|[Si6O18]}}, beryl (red: Si, blue: O) File:Benitoid.2200.png|3 units {{chem2|[Si3O9]}}, benitoite File:Papagoite.2200.png|4 units {{chem2|[Si4O12]}}, papagoite File:Eudialyte.2200.png|9 units {{chem2|[Si9O27]}}, eudialyte File:Milarite.png|12 units, double ring {{chem2|[Si12O30]}}, milarite </gallery>

Some example minerals are: * 3-member single ring ** Benitoite – {{chem2|BaTi(Si3O9)}} * 4-member single ring ** Papagoite – {{chem|CaCuAlSi|2|O|6|(OH)|3}}. * 6-member single ring **Beryl – {{chem2|Be3Al2(Si6O18)}} **Bazzite – {{chem2|Be3Sc2(Si6O18)}} **Sugilite – {{chem2|KNa2(Fe,Mn,Al)2Li3Si12O30}} **Tourmaline – {{chem|(Na,Ca)(Al,Li,Mg)|3–|(Al,Fe,Mn)|6|(Si|6|O|18|)(BO|3|)|3|(OH)|4|}} **Pezzottaite – {{chem2|Cs(Be2Li)Al2Si6O18}} **Osumilite – {{chem2|(K,Na)(Fe,Mg)2(Al,Fe)3(Si,Al)12O30}} **Cordierite – {{chem2|(Mg,Fe)2Al4Si5O18}} **Sekaninaite – {{chem2|(Fe^{+2},Mg)2Al4Si5O18}} * 9-member single ring ** Eudialyte – {{chem|Na|15|Ca|6|(Fe,Mn)|3|Zr|3|SiO|(O,OH,H|2|O)|3|(Si|3|O|9|)|2}}{{chem|(Si|9|O|27|)|2|(OH,Cl)|2}} * 6-member double ring **Milarite – {{chem2|K2Ca4Al2Be4(Si24O60)H2O}}

The ring in axinite contains two B and four Si tetrahedra and is highly distorted compared to the other 6-member ring cyclosilicates.

==Inosilicates== {{main category|Inosilicates}} Inosilicates (from Greek {{wikt-lang|grc|ἴς}} {{Transliteration|grc|is}} [genitive: {{wikt-lang|grc|ἰνός}} {{Transliteration|grc|inos}}] 'fibre'), or chain silicates, have interlocking chains of silicate tetrahedra with either {{chem2|SiO3}}, 1:3 ratio, for single chains or {{chem2|Si4O11}}, 4:11 ratio, for double chains. The Nickel–Strunz classification is 09.D – examples include:

===Single chain inosilicates=== *Pyroxene group<ref>{{cite web |title=Pyroxene Group |url=https://www.mindat.org/min-9767.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 October 2025}}</ref> **Clinopyroxene subgroup ***Aegirine (or acmite) – {{chem2|NaFe^{3+}Si2O6}} ***Augite – {{chem2|(Ca,Mg,Fe)2Si2O6}}<ref>{{cite web |title=Augite |url=https://www.mindat.org/min-419.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 October 2025}}</ref> ***Diopside – {{chem2|CaMgSi2O6}} ***Hedenbergite – {{chem2|CaFe^{2+}Si2O6}} ***Jadeite – {{chem2|Na(Al,Fe^{3+})Si2O6}} ***Pigeonite – {{chem2|(Ca_{x}Mg_{y}Fe_{z})(Mg_{y1}Fe_{z1})Si2O6}}, where 0.1 ≤ x ≤ 0.4, x + y + z = 1 and y1 + z1 = 1<ref>{{cite web |title=Pigeonite |url=https://www.mindat.org/min-3210.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 October 2025}}</ref> ***Spodumene – {{chem2|LiAlSi2O6}} **Orthopyroxene subgroup ***Enstatite – {{chem2|Mg2Si2O6}} ***Ferrosilite – {{chem2|Fe^{2+}2Si2O6}} *Pyroxferroite - {{chem2|(Fe,Mn,Ca)SiO3}}<ref>{{cite web |title=Pyroxferroite |url=https://www.mindat.org/min-3326.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 October 2025}}</ref> *Rhodonite – {{chem2|CaMn3Mn(Si5O15)}}<ref>{{cite web |title=Rhodonite |url=https://www.mindat.org/min-3407.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 October 2025}}</ref> *Wollastonite group<ref>{{cite web |title=Wollastonite Group |url=https://www.mindat.org/min-39542.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 October 2025}}</ref> **Pectolite – {{chem2|NaCa2Si3O8(OH)}} **Wollastonite – {{chem2|Ca3(Si3O9)}}

===Double chain inosilicates=== *Amphibole group **Anthophyllite – {{chem2|(Mg,Fe)7Si8O22(OH)2}} **Cummingtonite series ***Cummingtonite – {{chem2|Fe2Mg5Si8O22(OH)2}} ***Grunerite – {{chem2|Fe7Si8O22(OH)2}} **Tremolite series ***Tremolite – {{chem2|Ca2Mg5Si8O22(OH)2}} ***Actinolite – {{chem2|Ca2(Mg,Fe)5Si8O22(OH)2}} **Hornblende – {{chem|(Ca,Na)|2–3|(Mg,Fe,Al)|5|Si|6|(Al,Si)|2|O|22|(OH)|2|}} **Sodium amphibole group ***Glaucophane – {{chem2|Na2Mg3Al2Si8O22(OH)2}} ***Riebeckite (asbestos) – {{chem2|Na2Fe^{II}3Fe^{III}2Si8O22(OH)2}} ***Arfvedsonite – {{chem2|Na3(Fe,Mg)4FeSi8O22(OH)2}}

<gallery> File:Pyroxen-chain.png|Inosilicate, pyroxene family, with 2-periodic single chain {{chem2|(Si2O6)}}, diopside File:Tremolite-chain.png|Inosilicate, clinoamphibole, with 2-periodic double chains {{chem2|(Si4O11)}}, tremolite File:Wollastonite-chain.png|Inosilicate, unbranched 3-periodic single chain of wollastonite File:Rhodonite-chain.png|Inosilicate with 5-periodic single chain, rhodonite File:Pellyite-chain.png|Inosilicate with cyclic branched 8-periodic chain, pellyite </gallery>

==Phyllosilicates==<!-- Phyllosilicate and Sheet silicate redirect here. --> {{main category|Phyllosilicates}} '''Phyllosilicates''' (from Greek {{wikt-lang|grc|φύλλον}} {{Transliteration|grc|phýllon}} 'leaf'), or sheet silicates, form parallel sheets of silicate tetrahedra with {{chem2|Si2O5}} or a 2:5 ratio. The Nickel–Strunz classification is 09.E. All phyllosilicate minerals are hydrated, with either water or hydroxyl groups attached. Many phyllosilicates are clay-forming and may be further classified as 1:1 clay minerals (one tetrahedral sheet and one octahedral sheet) and 2:1 clay minerals (one octahedral sheet between two tetrahedral sheets). Below are some major phyllosilicate mineral species and their chemical formulas, with group and series names in italics: thumb|Kaolinite *Ajoite – {{chem2|(K,Na)Cu7AlSi9O24(OH)6*3H2O}}<ref>{{cite web |title=Ajoite |url=https://www.mindat.org/min-66.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=18 July 2025}}</ref> *''Apophyllite group''<ref>{{cite web |title=Apophyllite Group |url=https://www.mindat.org/min-283.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=18 July 2025}}</ref> **Fluorapophyllite-(K) – {{chem2|KCa4(Si8O22)F*8H2O}} *Bannisterite – {{chem2|(Ca,K,Na)(Mn^{2+},Fe^{2+})10(Si,Al)16O38(OH)8*nH2O}}<ref>{{cite web |title=Bannisterite |url=https://www.mindat.org/min-509.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=18 July 2025}}</ref> *Carletonite – {{chem2|KNa4Ca4Si8O18(CO3)4(OH,F)*H2O}}<ref>{{cite web |title=Carletonite |url=https://www.mindat.org/min-898.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=18 July 2025}}</ref> *Cavansite – {{chem2|Ca(VO)Si4O10*4H2O}}{{quad}}(dimorph of pentagonite)<ref>{{cite web |title=Cavansite |url=https://www.mindat.org/min-921.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=18 July 2025}}</ref> *''Chlorite group''<ref>{{cite web |title=Chlorite Group |url=https://www.mindat.org/min-1016.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=1 July 2025}}</ref> – {{chem2|(Al,Fe^{2+},Fe^{3+}Li,Mg,Mn,Ni)_{5-6}(Al,Fe^{3+},Si)4(O,OH)18}}{{quad}}(2:1:1 clays) **Chamosite – {{chem2|(Fe^{2+},Mg,Al,Fe^{3+})6(Si,Al)4O10(OH,O)8}}{{quad}}(Fe endmember) **Clinochlore – {{chem2|Mg5Al(AlSi3O10)(OH)8}}{{quad}}(Mg endmember) **Cookeite – {{chem2|(LiAl4◻)[AlSi3O10](OH)8}} *Chrysocolla – {{chem2|Cu_{2-x}Alx(H_{2-x}Si2O5)(OH)4*nH2O, x < 1}}<ref>{{cite web |title=Chrysocolla |url=https://www.mindat.org/min-1040.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=22 July 2025}}</ref> *Ekanite – {{chem2|Ca2ThSi8O20}}<ref>{{cite web |title=Ekanite |url=https://www.mindat.org/min-1361.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 July 2025}}</ref> *Gyrolite – {{chem2|NaCa16Si23AlO60(OH)8*14H2O}}<ref>{{cite web |title=Gyrolite |url=https://www.mindat.org/min-1785.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 July 2025}}</ref> *Hisingerite – {{chem2|Fe^{3+}2(Si2O5)(OH)4*2H2O}}<ref>{{cite web |title=Hisingerite |url=https://www.mindat.org/min-1910.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 July 2025}}</ref> *Imogolite – {{chem2|Al2SiO3(OH)4}}<ref>{{cite web |title=Imogolite |url=https://www.mindat.org/min-2021.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 July 2025}}</ref> *''Kaolinite-Serpentine group''<ref>{{cite web |title=Kaolinite-Serpentine Group |url=https://www.mindat.org/min-11136.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=25 June 2025}}</ref> **Greenalite – {{chem2|(Fe^{2+},Fe^{3+})_{2-3}Si2O5(OH)4}} **''Kaolinite subgroup''{{quad}}(1:1 clays) ***Dickite – {{chem2|Al2(Si2O5)(OH)4}} ***Kaolinite – {{chem2|Al2Si2O5(OH)4}} ***Halloysite – {{chem2|Al2Si2O5(OH)4}} **''Serpentine subgroup'' ***Amesite – {{chem2|Mg2Al(AlSiO5)(OH)4}} ***Antigorite – {{chem2|Mg3Si2O5(OH)4}} ***Chrysotile – {{chem2|Mg3Si2O5(OH)4}} ***Lizardite – {{chem2|Mg3Si2O5(OH)4}} *''Mica group''<ref>{{cite web |title=Mica Group |url=https://www.mindat.org/min-6728.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 February 2025}}</ref> **''Brittle mica group''<ref>{{cite web |title=Brittle Mica |url=https://www.mindat.org/min-43757.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 February 2025}}</ref> ***Clintonite – {{chem2|CaAlMg2(SiAl3O10)(OH)2}} ***Margarite – {{chem2|CaAl2(Al2Si2)O10(OH)2}} **''Dioctahedral mica group'' ***''Celadonite subgroup'' ****Celadonite – {{chem2|K(MgFe^{3+}◻)(Si4O10)(OH)2}} ***Glauconite – {{chem2|K_{0.60-0.85}(Fe^{3+},Mg,Al)2(Si,Al)4O10](OH)2}} ***Muscovite – {{chem2|KAl2(AlSi3)O10(OH)2}}<ref>{{cite web |title=Muscovite |url=https://www.mindat.org/min-2815.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 February 2025}}</ref> ***Paragonite – {{chem2|NaAl2(AlSi3O10)(OH)2}} ***Roscoelite – {{chem2|K(V^{3+},Al)2(AlSi3O10)(OH)2}} **''Trioctahedral mica group'' ***Aspidolite – {{chem2|NaMg3(AlSi3O10)(OH)2}} ***''Biotite subgroup'' – {{chem2|K(Fe^{2+},Mg)2(Al,Fe^{3+},Mg,Ti)([Si,Al,Fe]2Si2O10)(OH,F)2}} ****Annite – {{chem2|KFe^{2+}3(AlSi3O10)(OH)2}}{{quad}}(Fe endmember) ****Phlogopite – {{chem2|KMg3(AlSi3)O10(OH)2}}{{quad}}(Mg endmember) ***''Lepidolite (polylithionite-trilithionite series)'' – {{chem2|K(Li2,Li1.5Al1.5)AlSi_{3-4}O10(F,OH)2}} ***''Zinnwaldite series'' – {{chem2|KFe^{2+}2Al(Al2Si2O10)(OH)2}} *Neptunite – {{chem2|KNa2Li(Fe^{2+})2Ti2[Si4O12]2}}<ref>{{cite web |title=Neptunite |url=https://www.mindat.org/min-2883.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 July 2025}}</ref> *Okenite – {{chem2|Ca10Si18O46*18H2O}}<ref>{{cite web |title=Okenite |url=https://www.mindat.org/min-2967.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 July 2025}}</ref> *''Palygorskite group''<ref>{{cite web |title=Palygorskite |url=https://www.mindat.org/min-3072.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=1 July 2025}}</ref>{{quad}}(2:1 clays) **Palygorskite – {{chem2|◻Al2Mg2◻2Si8O20(OH)2(H2O)4*4H2O}} **Tuperssuatsiaite – {{chem2| Fe^{3+}Fe^{3+}2(Na◻)◻2Si8O20(OH)2(H2O)4*2H2O}} *Pentagonite – {{chem2|Ca(VO)Si4O10*4H2O}}{{quad}}(dimorph of cavansite)<ref>{{cite web |title=Pentagonite |url=https://www.mindat.org/min-3152.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=28 July 2025}}</ref> *''Pyrophyllite-Talc group''<ref>{{cite web |title=Pyrophyllite-Talc Group |url=https://www.mindat.org/min-39702.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=26 June 2025}}</ref> **Pyrophyllite – {{chem2|Al2Si4O10(OH)2}} **Talc – {{chem2|Mg3Si4O10(OH)2}}{{quad}}(2:1 clay) *''Sepiolite group'' **Sepiolite – {{chem2|Mg4(Si6O15)(OH)2*6H2O}}<ref>{{cite web |title=Sepiolite |url=https://www.mindat.org/min-3621.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=1 July 2025}}</ref>{{quad}}(2:1 clay) **Falcondoite – {{chem2|(Ni,Mg)4Si6O15(OH)2*6H2O}}{{quad}}(Ni analogue of sepiolite)<ref>{{cite web |title=Falcondoite |url=https://www.mindat.org/min-1444.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 July 2025}}</ref> *''Smectite group''<ref>{{cite web |title=Smectite Group |url=https://www.mindat.org/min-11119.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=25 June 2025}}</ref>{{quad}}(2:1 clays) **Hectorite – {{chem2|Na0.3(Mg,Li)3(Si4O10)(F,OH)2}} **Montmorillonite – {{chem2|(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2*nH2O}} **Nontronite – {{chem2|Na0.3Fe2((Si,Al)4O10)(OH)2*nH2O}} **Saponite – {{chem2|Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2*nH2O}} **Stevensite – {{chem2|(Ca,Na)_{x}Mg_{3-x}(Si4O10)(OH)2}} *''Stilpnomelane group''<ref>{{cite web |title=Stilpnomelane Group |url=https://www.mindat.org/min-46595.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=24 July 2025}}</ref> **Stilpnomelane – {{chem2|(K,Ca,Na)(Fe,Mg,Al)8(Si,Al)12(O,OH)36*nH2O}} *Vermiculite – {{chem2|Mg0.7(Mg,Fe,Al)6(Si,Al)8O20(OH)4*8H2O}}<ref>{{cite web |title=Vermiculite |url=https://www.mindat.org/min-4170.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=1 July 2025}}</ref>{{quad}}(2:1 clay)

<gallery> File:Muskovite.sheet.png|Phyllosilicate, mica group, muscovite (red: Si, blue: O) File:Apophyllite.sheet.png|Phyllosilicate, single net of tetrahedra with 4-membered rings, apophyllite group File:Pyrosmalite.sheet.png|Phyllosilicate, single tetrahedral nets of 6-membered rings, pyrosmalite-(Fe)-pyrosmalite-(Mn) series File:Zeophyllite.sheet.png|Phyllosilicate, single tetrahedral nets of 6-membered rings, zeophyllite File:Carletonite.sheet.png|Phyllosilicate, double nets with 4- and 6-membered rings, carletonite </gallery>

== Tectosilicates == {{main category|Tectosilicates}} [[File:Beta-quartz-CM-2D-balls.png|thumb|Silica family {{chem2|(SiO2}} 3D network), β-quartz]] [[File:Zeolite-ZSM-5-vdW.png|thumb|Aluminosilicate family, the 3D model of synthetic zeolite ZSM-5]] [[Image:Quartz oisan.jpg|thumb|Quartz]] [[Image:Lunar Ferroan Anorthosite (60025).jpg|thumb|Lunar ferroan anorthosite (plagioclase feldspar) collected by Apollo 16 astronauts from the Lunar Highlands near Descartes Crater]] Tectosilicates, or "framework silicates," have a three-dimensional framework of silicate tetrahedra with {{chem2|SiO2}} in a 1:2 ratio. This group comprises nearly 75% of the crust of the Earth.<ref name=deer4B>{{Cite book| last = Deer| first = W.A. |author2=Howie, R.A. |author3=Wise, W.S. |author4=Zussman, J.| year = 2004| title = Rock-forming minerals. Volume 4B. Framework silicates: silica minerals. Feldspathoids and the zeolites| edition = 2nd| publisher = Geological Society of London| location = London| page = 982 pp}}</ref> Tectosilicates, with the exception of the quartz group, are aluminosilicates. The Nickel–Strunz classifications are 9.F (tectosilicates without zeolitic {{chem2|H2O}}), 9.G (tectosilicates with zeolitic {{chem2|H2O}}), and 4.DA (quartz/silica group). Below are some major tectosilicate mineral species and their chemical formulas, with group and series names in italics: *''Quartz group (silica)'' – {{chem2|SiO2}} **Chalcedony – cryptocrystalline variety of silica composed mostly of quartz with some moganite **Polymorphs of silica ***α-quartz – trigonal, "normal" quartz under {{convert|573|C|K F}} ***β-quartz – hexagonal, high-temperature quartz ***Coesite – monoclinic ***Cristobalite – tetragonal ***Melanophlogite – cubic or tetragonal, rare ***Moganite – monoclinic ***Stishovite – tetragonal, extremely hard and dense ***Tridymite – orthorhombic *''Feldspar group''<ref>{{cite web |title=Feldspar Group |url=https://www.mindat.org/min-1624.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> **''Alkali feldspar series (potassium feldspars or K-spar)'' ***Microcline – {{chem2|KAlSi3O8}} ***Orthoclase – {{chem2|KAlSi3O8}} ***Anorthoclase – {{chem2|(Na,K)AlSi3O8}} ***Sanidine – {{chem2|KAlSi3O8}} **''Plagioclase feldspar series'' ***Albite – {{chem2|NaAlSi3O8}}{{quad}}(Na endmember) ***Oligoclase – {{chem2|(Na,Ca)Al(Si,Al)Si2O8}}{{quad}}(Na:Ca 90:10 to 70:30)<ref>{{cite web |title=Oligoclase |url=https://www.mindat.org/min-2976.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> ***Andesine – {{chem2|(Na,Ca)Al(Si,Al)Si2O8}}{{quad}}(Na:Ca 50:50 to 70:30)<ref>{{cite web |title=Andesine |url=https://www.mindat.org/min-220.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> ***Labradorite – {{chem2|(Ca,Na)Al(Al,Si)Si2O8}}{{quad}}(Na:Ca 30:70 to 50:50)<ref>{{cite web |title=Labradorite |url=https://www.mindat.org/min-2308.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> ***Bytownite – {{chem2|(Ca,Na)Al(Al,Si)Si2O8}}{{quad}}(Na:Ca 10:90 to 30:70)<ref>{{cite web |title=Bytownite |url=https://www.mindat.org/min-815.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> ***Anorthite – {{chem2|CaAl2Si2O8}}{{quad}}(Ca endmember) **Other feldspars ***Buddingtonite — {{chem2|NH4AlSi3O8}} ***Celsian – {{chem2|BaAl2Si2O8}} ***Hyalophane – {{chem2|(K,Ba)[Al(Si,Al)Si2O8]}}<ref>{{cite web |title=Hyalophane |url=https://www.mindat.org/min-1960.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> *''Feldspathoid group''<ref>{{cite web |title=Feldspathoid |url=https://www.mindat.org/min-47865.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> **''Cancrinite subgroup'' ***Afghanite – {{chem2|(Na,K)22Ca10[Si24Al24O96](SO4)6Cl6}} ***Cancrinite – {{chem2|(Na,Ca,◻)8(Al6Si6O24)(CO3,SO4)2*2H2O}} ***Sacrofanite – {{chem2|(Na61K19Ca32)(Si84Al84O336)(SO4)26Cl2F6*2H2O}} **Leucite – {{chem2|K(AlSi2O6)}} **''Nepheline subgroup'' ***Nepheline – {{chem2|Na3K(Al4Si4O16)}} **''Sodalite subgroup'' ***Hauyne – {{chem2|Na3Ca(Si3Al3)O12(SO4)}} ***Lazurite – {{chem2|Na7Ca(Al6Si6O24)(SO4)(S3)*H2O}} ***Nosean – {{chem2|Na8(Al6Si6O24)(SO4)*H2O}} ***Sodalite – {{chem2|Na4(Si3Al3)O12Cl}} ***Tugtupite – {{chem2|Na4(BeAlSi4O12)Cl}}<ref>{{cite web |title=Tugtupite |url=https://www.mindat.org/min-4044.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> *''Scapolite group''<ref>{{cite web |title=Scapolite |url=https://www.mindat.org/min-8778.html |website=mindat.org |publisher=Hudson Institute of Mineralogy |access-date=23 February 2025}}</ref> **Marialite – {{chem2|Na4Al3Si9O24Cl}} **Meionite – {{chem2|Ca4Al6Si6O24CO3}} *''Zeolite group''<ref>{{Cite web |title=Zeolite Group |url=https://www.mindat.org/min-4395.html |access-date=2025-02-22 |website=www.mindat.org}}</ref> **Amicite – {{chem2| K2Na2Al4Si4O16*5H2O}} **Analcime – {{chem2|Na(AlSi2O6)*H2O}} **''Brewsterite subgroup'' – {{chem2| (Ba,Sr,Ca)Al2Si6O16*5H2O}} **''Chabazite-Lévyne subgroup'' ***Chabazite – {{chem2|''M''[Al2Si4O12]*6H2O}} ***Lévyne – {{chem2|(Ca_{1-2},Na_{1-2},K2)Al2Si4O12*6H2O}} **''Clinoptilolite subgroup'' – {{chem2|(Na,Ca,K)_{3-6}(Al_{6-7}Si_{29-30}O72)*20H2O}} **''Erionite subgroup'' – {{chem2|(Na_{1-2},K_{1-2},Ca_{1-2})2Al4Si14O36*15H2O}} **''Faujasite subgroup'' – {{chem2| (Na_{1-2},Ca_{1-2},Mg_{1-2})3.5[Al7Si17O48]*32H2O}} **''Ferrierite subgroup'' – {{chem2|[Mg2(K,Na)2Ca0.5](Si29Al7)O72*18H2O}}{{quad}}(Ferrierite-Mg) **''Heulandite subgroup'' – {{chem2|(Na,Ca,K)_{5-6}[Al_{8-9}Si_{27-28}O72]*nH2O}} **Laumontite – {{chem2|CaAl2Si4O12*4H2O}} **Mordenite – {{chem2|(Na2,Ca,K2)4(Al8Si40)O96*28H2O}} **''Natrolite subgroup'' ***Mesolite – {{chem2|Na2Ca2Si9Al6O30*8H2O}} ***Natrolite – {{chem2|Na2Al2Si3O10*2H2O}} ***Scolecite – {{chem2|CaAl2Si3O10*3H2O}} **''Paulingite subgroup'' – {{chem2|(K2,Ca,Na2,Ba)5[Al10Si35O90]*45H2O}}{{quad}}(Paulingite-K) **''Phillipsite subgroup'' ***Phillipsite – {{chem2|(Ca3(Si10Al6)O32*12H2O}}{{quad}}(Phillipsite-Ca) **Pollucite – {{chem2|(Cs,Na)2(Al2Si4O12)*2H2O}} **''Stilbite subgroup'' ***Stellerite – {{chem2|Ca4(Si28Al8)O72*28H2O}} ***Stilbite – {{chem2|(NaCa4,Na9)(Si27Al9)O72*28H2O}} **Thomsonite subgroup – {{chem2|NaCa2Al5Si5O20*6H2O}}{{quad}}(Thomsonite-Ca) **Yugawaralite – {{chem2|CaAl2Si6O16*4H2O}}

==See also== {{Portal|Earth sciences}} * {{annotated link|Classification of non-silicate minerals}} * {{annotated link|Classification of silicate minerals}} * {{annotated link|Silicate mineral paint}}

==References== {{reflist}}

==External links== {{Wikibooks|Historical Geology|Silicate minerals}} {{Commons category|Silicate minerals}} * [http://www.mindat.org/dana.php Mindat.org, Dana classification] * [http://webmineral.com/dana/8_Silicates.shtml Webmineral : Dana's New Silicate Classification]

{{Strunz}} {{Authority control}}

Category:Silicate minerals