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About MagnesiochloritoidHide

Crystal System:
Named as the Mg analogue of chloritoid. The name was originally published without IMA approval.
Monoclinic and triclinic polytypes are known.

Classification of MagnesiochloritoidHide


9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination

52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
3 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [6] coordination only

16 : Silicates Containing Aluminum and other Metals
7 : Aluminosilicates of Mg

Physical Properties of MagnesiochloritoidHide

6½ on Mohs scale

Optical Data of MagnesiochloritoidHide

r < v moderate

Chemical Properties of MagnesiochloritoidHide

IMA Formula:

Crystallography of MagnesiochloritoidHide

Crystal System:
Class (H-M):
2/m - Prismatic
Space Group:
Cell Parameters:
a = 9.460(1) Å, b = 5.471(1) Å, c = 18.182(2) Å
β = 101.4(1)°
a:b:c = 1.729 : 1 : 3.323
Unit Cell V:
922.46 ų (Calculated from Unit Cell)
Common on {001}, polysynthetic.

Type Occurrence of MagnesiochloritoidHide

Other Language Names for MagnesiochloritoidHide

Relationship of Magnesiochloritoid to other SpeciesHide

Other Members of this group:
Chloritoid(Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2Mon. 2/m : B2/b

Common AssociatesHide

Associated Minerals Based on Photo Data:
Spessartine2 photos of Magnesiochloritoid associated with Spessartine on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.AF.05SillimaniteAl2(SiO4)OOrth. mmm (2/m 2/m 2/m)
9.AF.10AndalusiteAl2(SiO4)OOrth. mmm (2/m 2/m 2/m) : Pnnm
9.AF.10KanonaiteMn3+Al(SiO4)OOrth. mmm (2/m 2/m 2/m) : Pnnm
9.AF.15KyaniteAl2(SiO4)OTric. 1 : P1
9.AF.20MulliteAl4+2xSi2-2xO10-xOrth. mmm (2/m 2/m 2/m) : Pbam
9.AF.20Krieselite(Al,Ga)2(GeO4)(OH)2Orth. mmm (2/m 2/m 2/m) : Pnma
9.AF.23BoromulliteAl9BSi2O19Orth. mm2 : Cmc21
9.AF.25YoderiteMg(Al,Fe3+)3(SiO4)2O(OH)Mon. 2/m : P21/m
9.AF.30MagnesiostauroliteMg(Mg,Li)3(Al,Mg)18Si8O44(OH)4Mon. 2/m : B2/m
9.AF.30StauroliteFe2+2Al9Si4O23(OH)Mon. 2/m : B2/m
9.AF.30ZincostauroliteZn2Al9Si4O23(OH)Mon. 2/m : B2/m
9.AF.35TopazAl2(SiO4)(F,OH)2Orth. mmm (2/m 2/m 2/m)
9.AF.40NorbergiteMg3(SiO4)(F,OH)2Orth. mmm (2/m 2/m 2/m)
9.AF.45AlleghanyiteMn2+5(SiO4)2(OH)2Mon. 2/m : P21/b
9.AF.45Chondrodite(Mg,Fe2+)5(SiO4)2(F,OH)2Mon. 2/m : P21/b
9.AF.45ReinhardbraunsiteCa5(SiO4)2(OH,F)2Mon. 2/m : P21/b
9.AF.45KumtyubeiteCa5(SiO4)2F2Mon. 2/m : P21/b
9.AF.45HydroxylchondroditeMg5(SiO4)2(OH)2Mon. 2/m : P21/b
9.AF.50Humite(Mg,Fe2+)7(SiO4)3(F,OH)2Orth. mmm (2/m 2/m 2/m) : Pnma
9.AF.50Unnamed (Ca-analogue of Humite)Ca7(SiO4)4F2Orth. mmm (2/m 2/m 2/m)
9.AF.55ClinohumiteMg9(SiO4)4F2Mon. 2/m : P21/b
9.AF.55HydroxylclinohumiteMg9(SiO4)4(OH)2Mon. 2/m
9.AF.60LeucophoeniciteMn2+7(SiO4)3(OH)2Mon. 2/m : P21/b
9.AF.70JerrygibbsiteMn2+9(SiO4)4(OH)2Orth. mmm (2/m 2/m 2/m) : Pbcn
9.AF.75WeliniteMn2+6(W6+,Mg)2(SiO4)2(O,OH)6Trig. 3 : P3
9.AF.85Chloritoid(Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2Mon. 2/m : B2/b
9.AF.90PoldervaartiteCaCa[SiO3(OH)](OH)Orth. mmm (2/m 2/m 2/m) : Pbca
9.AF.90OlmiiteCaMn2+[SiO3(OH)](OH)Orth. mmm (2/m 2/m 2/m) : Pbca

Related Minerals - Dana Grouping (8th Ed.)Hide,Mg,Mn2+)Al2(SiO4)O(OH)2Mon. 2/m : B2/bélite(Mn2+,Fe2+,Mg)Al2(SiO4)O(OH)2Mon. 2/m : P21/b 2/m : P21/b

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

16.7.2SapphirineMg4(Mg3Al9)O4[Si3Al9O36]Mon. 2/m : P21/b
16.7.3Sapphirine-1A(Mg,Al,Fe2+)8[(Al,Si,Fe3+)6O18]O2Tric. 1 : P1
16.7.6Palygorskite(Mg,Al)5(Si,Al)8O20(OH)2 · 8H2OMon. 2/m : B2/m
16.7.7SaponiteCa0.25(Mg,Fe)3((Si,Al)4O10)(OH)2 · nH2OMon.
16.7.8AliettiteCa0.2Mg6((Si,Al)8O20)(OH)4 · 4H2OMon.
16.7.9Montmorillonite(Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2OMon. 2/m : B2/m

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for MagnesiochloritoidHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Chopin, C. and Schreyer, W. (1983) Magnesio-carpholite and magnesiochloritoid: two index minerals of pelitic blueschists and their preliminary phase relations n the model system MgO-Al2O3-SiO2-H2O. American Journal of Science: 283-A: 72-96.
Chopin, C. (1983): Magnesiochloritoid, a key-mineral for the petrogenesis of high-grade pelitic blueschists. Bulletin de Minéralogie 106, 715-717.
American Mineralogist (1985): 70: 216-217.
Ivaldi, G., Catti, M., Ferraris, G. (1988): Crystal structure at 25 and 700 °C of magnesiochloritoid from a high-pressure assemblage (Monte Rosa). American Mineralogist 73, 358-364.
Comodi, P., Mellini, M., Zanazzi, P.F. (1992): Magnesiochloritoid: Compressibility and high pressure structure refinement. Physics and Chemistry of Minerals 18, 483-490.

Internet Links for MagnesiochloritoidHide

Localities for MagnesiochloritoidHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
  • Jiangsu
    • Lianyungang
      • Donghai Co.
        • Zhimafang
Zhang, R.Y., Liou, J.G., and Zheng, J.P. (2004): Contributions to Mineralogy and Petrology 147, 21-31.
  • Aosta Valley
    • Ayas Valley
      • Ayas
        • Champoluc
Chopin, C., Seidel, E. Theye, T., Ferraris, G., Ivaldi, G., Catti, M. (1992) Magnesiochloritoid, and the Fe-Mg series in the chloritid group. European Journal of Mineralogy, 4, 67-76.
Dal Piaz, G.V., Gianotti, F., Monopoli, B., Pennacchioni, G., Tartarotti, P., Schiavo, A., with contributions of Carraro, F., Bistacchi, A., Massironi, M., Martin, S., Ratto, S., (2008) Note illustrative della Carta geologica d’Italia alla scala 1:50.000, foglio 091, Châtillon. Apat - Agenzia per la protezione dell'ambiente e i servizi tecnici, Dipartimento Difesa del Suolo - Servizio Geologico d’Italia, Regione Autonoma Valle d'Aosta, B. Monopoli - Land Technology & Services, Treviso, and La Nuova Lito, Firenze, 152 pp.
    • Saint-Marcel
Piccoli, G.C., Maletto, G., Bosio, P., Lombardo, B. (2007): Minerali del Piemonte e della Valle d'Aosta. Associazione Amici del Museo "F. Eusebio" Alba, Ed., Alba (Cuneo) 607 pp.
  • Piedmont
    • Cuneo Province
Lithos, 41: 37-57.
      • Po Valley
        • Monviso
Messiga et al. : "Cr-rich Magnesiochloritoid Eclogites from the Monviso ophiolites (Western Alps Italy)", Journal of Metamorphic Geology, Vol 17, Issue 3, p. 287, May 1999.
      • Varaita Valley
        • Brossasco
Piccoli, G.C., Maletto, G., Bosio, P., Lombardo, B. (2007). Minerali del Piemonte e della Valle d'Aosta. Associazione Amici del Museo "F. Eusebio" Alba, Ed., Alba (Cuneo) 607 pp.
  • Andalusia
    • Granada
      • Otívar
Eur. J. Mineral. , 1989, 1, pp. 139-142..
  • Madrid
    • La Hiruela
  • Wallis (Valais)
    • Zermatt - Saas Fee area
      • Matt Valley
Stalder, H. A., Wagner, A., Graeser, S. and Stuker, P. (1998): "Mineralienlexikon der Schweiz", Wepf (Basel), p. 261.
        • Zermatt
          • Gorner glacier area
            • Stockhorn
Cont. to Mineralogy and Petrology 87:388-398
      • Saas Valley
        • Saas-Almagell
          • Allalin area
Bearth, P. (1963): Chloritoid und Paragonit aus der Ophiolit-Zone von Zermatt-Saas Fee. Schweizerische Mineralogische und Petrographische Mitteilungen, 43, 269-286; Stalder, H.A., Wagner, A., Graeser, S., Stuker, P. (1998): Mineralienlexikon der Schweiz. Wepf Verlag, Basel, pages 261-262; Roth, Ph. (2007): Minerals first discovered in Switzerland and minerals named after Swiss individuals. Philippe Roth, Ed., Zurich, 239 pp.
Mineral and/or Locality  
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