Ottrélite
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About Ottrélite
Formula:
(Mn2+,Fe2+,Mg)Al2(SiO4)O(OH)2
Colour:
Pistachio-green, greenish to dark grey
Hardness:
6 - 7
Crystal System:
Monoclinic
Member of:
Name:
Named by A. Descloizeaux and A.A. Damour in 1842 for the type locality of Ottré, Belgium.
Mn analogue of chloritoid. Ottrélite was originally described as a Mn-rich, but not necessarily Mn-dominant chloritoid, consequently many "ottrélites" are in reality Mn-rich chloritoids, see Chloritoid best minerals article and references therein for further details.
Typically occurs in low- and medium-grade metamorphic rocks.
Monoclinic and triclinic polytypes are known.
Typically occurs in low- and medium-grade metamorphic rocks.
Monoclinic and triclinic polytypes are known.
Classification of Ottrélite
Approved, 'Grandfathered' (first described prior to 1959)
8/B.24-30
9.AF.85
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
52.3.3.3
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
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
16.16.21
16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
Physical Properties of Ottrélite
Optical Data of Ottrélite
Type:
Biaxial (+)
RI values:
nα = 1.709 - 1.725 nβ = 1.712 - 1.726 nγ = 1.716 - 1.732
2V:
Measured: 46° to 70°, Calculated: 46° to 82°
Max Birefringence:
δ = 0.007

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
High
Dispersion:
r > v strong
Chemical Properties of Ottrélite
Formula:
(Mn2+,Fe2+,Mg)Al2(SiO4)O(OH)2
IMA Formula:
Mn2+Al2O(SiO4)(OH)2
Common Impurities:
Ca,H2O
Crystallography of Ottrélite
Crystal System:
Monoclinic
Cell Parameters:
a = 9.505(6) Å, b = 5.484(4) Å, c = 18.214(15) Å
β = 101.77(3)°
β = 101.77(3)°
Ratio:
a:b:c = 1.733 : 1 : 3.321
Unit Cell V:
929.45 ų (Calculated from Unit Cell)
Twinning:
Polysynthetic, parallel to [001].
Comment:
Space group Cc or C2/c. Pseudohexagonal.
Type Occurrence of Ottrélite
Synonyms of Ottrélite
Other Language Names for Ottrélite
Relationship of Ottrélite to other Species
Member of:
Other Members of this group:
Carboirite | FeAl2(GeO4)O(OH)2 | Tric. |
Chloritoid | (Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2 | Mon. 2/m : B2/b |
Magnesiochloritoid | MgAl2(SiO4)O(OH)2 | Mon. 2/m : B2/b |
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Nickel-Strunz Grouping
9.AF.05 | Sillimanite | Al2(SiO4)O | Orth. mmm (2/m 2/m 2/m) |
9.AF.10 | Andalusite | Al2(SiO4)O | Orth. mmm (2/m 2/m 2/m) : Pnnm |
9.AF.10 | Kanonaite | Mn3+Al(SiO4)O | Orth. mmm (2/m 2/m 2/m) : Pnnm |
9.AF.15 | Kyanite | Al2(SiO4)O | Tric. 1 : P1 |
9.AF.20 | Mullite | Al4+2xSi2-2xO10-x | Orth. mmm (2/m 2/m 2/m) : Pbam |
9.AF.20 | Krieselite | (Al,Ga)2(GeO4)(OH)2 | Orth. mmm (2/m 2/m 2/m) : Pnma |
9.AF.23 | Boromullite | Al9BSi2O19 | Orth. mm2 : Cmc21 |
9.AF.25 | Yoderite | Mg(Al,Fe3+)3(SiO4)2O(OH) | Mon. 2/m : P21/m |
9.AF.30 | Magnesiostaurolite | Mg(Mg,Li)3(Al,Mg)18Si8O44(OH)4 | Mon. 2/m : B2/m |
9.AF.30 | Staurolite | Fe2+2Al9Si4O23(OH) | Mon. 2/m : B2/m |
9.AF.30 | Zincostaurolite | Zn2Al9Si4O23(OH) | Mon. 2/m : B2/m |
9.AF.35 | Topaz | Al2(SiO4)(F,OH)2 | Orth. mmm (2/m 2/m 2/m) |
9.AF.40 | Norbergite | Mg3(SiO4)(F,OH)2 | Orth. mmm (2/m 2/m 2/m) |
9.AF.45 | Alleghanyite | Mn2+5(SiO4)2(OH)2 | Mon. 2/m : P21/b |
9.AF.45 | Chondrodite | (Mg,Fe2+)5(SiO4)2(F,OH)2 | Mon. 2/m : P21/b |
9.AF.45 | Reinhardbraunsite | Ca5(SiO4)2(OH,F)2 | Mon. 2/m : P21/b |
9.AF.45 | Kumtyubeite | Ca5(SiO4)2F2 | Mon. 2/m : P21/b |
9.AF.45 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 | Mon. 2/m : P21/b |
9.AF.50 | Humite | (Mg,Fe2+)7(SiO4)3(F,OH)2 | Orth. mmm (2/m 2/m 2/m) : Pnma |
9.AF.50 | Manganhumite | (Mn2+,Mg)7(SiO4)3(OH)2 | Orth. |
9.AF.50 | Unnamed (Ca-analogue of Humite) | Ca7(SiO4)4F2 | Orth. mmm (2/m 2/m 2/m) |
9.AF.55 | Clinohumite | Mg9(SiO4)4F2 | Mon. 2/m : P21/b |
9.AF.55 | Sonolite | Mn2+9(SiO4)4(OH)2 | Mon. |
9.AF.55 | Hydroxylclinohumite | Mg9(SiO4)4(OH)2 | Mon. 2/m |
9.AF.60 | Leucophoenicite | Mn2+7(SiO4)3(OH)2 | Mon. 2/m : P21/b |
9.AF.65 | Ribbeite | Mn2+5(SiO4)2(OH)2 | Orth. |
9.AF.70 | Jerrygibbsite | Mn2+9(SiO4)4(OH)2 | Orth. mmm (2/m 2/m 2/m) : Pbcn |
9.AF.75 | Franciscanite | Mn2+6(V5+,☐)2(SiO4)2(O,OH)6 | Hex. |
9.AF.75 | Örebroite | Mn2+3(Sb5+,Fe3+)(SiO4)(O,OH)3 | Hex. |
9.AF.75 | Welinite | Mn2+6(W6+,Mg)2(SiO4)2(O,OH)6 | Trig. 3 : P3 |
9.AF.80 | Ellenbergerite | Mg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10 | Hex. |
9.AF.85 | Chloritoid | (Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2 | Mon. 2/m : B2/b |
9.AF.85 | Magnesiochloritoid | MgAl2(SiO4)O(OH)2 | Mon. 2/m : B2/b |
9.AF.90 | Poldervaartite | CaCa[SiO3(OH)](OH) | Orth. mmm (2/m 2/m 2/m) : Pbca |
9.AF.90 | Olmiite | CaMn2+[SiO3(OH)](OH) | Orth. mmm (2/m 2/m 2/m) : Pbca |
Related Minerals - Dana Grouping (8th Ed.)
52.3.3.1 | Chloritoid | (Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2 | Mon. 2/m : B2/b |
52.3.3.2 | Magnesiochloritoid | MgAl2(SiO4)O(OH)2 | Mon. 2/m : B2/b |
52.3.3.4 | Carboirite | FeAl2(GeO4)O(OH)2 | Tric. |
52.3.3.4 | Kumtyubeite | Ca5(SiO4)2F2 | Mon. 2/m : P21/b |
52.3.3.6 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 | Mon. 2/m : P21/b |
Related Minerals - Hey's Chemical Index of Minerals Grouping
16.16.1 | Kanonaite | Mn3+Al(SiO4)O | Orth. mmm (2/m 2/m 2/m) : Pnnm |
16.16.2 | Spessartine | Mn2+3Al2(SiO4)3 | Iso. m3m (4/m 3 2/m) : Ia3d |
16.16.3 | Davreuxite | MnAl6Si4O17(OH)2 | Mon. |
16.16.4 | Sursassite | Mn2+2Al3(SiO4)(Si2O7)(OH)3 | Mon. 2/m : P21/m |
16.16.5 | Carpholite | Mn2+Al2(Si2O6)(OH)4 | Orth. |
16.16.6 | Kellyite | Mn2+2Al(AlSiO5)(OH)4 | Hex. 6 : P63 |
16.16.7 | Pennantite | Mn2+5Al(AlSi3O10)(OH)8 | Tric. |
16.16.8 | Akatoreite | Mn2+9Al2Si8O24(OH)8 | Tric. |
16.16.9 | Ganophyllite | (K,Na,Ca)2Mn8(Si,Al)12(O,OH)32 · 8H2O | Mon. |
16.16.10 | Mangano-ferri-eckermannite | {Na}{Na2}{Mn2+4Fe3+}Si8O22(OH)2 | Mon. |
16.16.11 | Masutomilite | (K,Rb)(Li,Mn3+,Al)3(AlSi3O10)(F,OH)2 | Mon. |
16.16.13 | Howieite | Na(Fe,Mn)10(Fe,Al)2Si12O31(OH)13 | Tric. |
16.16.14 | Eggletonite | (Na,K,Ca)2(Mn,Fe)8(Si,Al)12O29(OH)7 · 11H2O | Mon. |
16.16.15 | Bannisterite | (Ca,K,Na)(Mn2+,Fe2+)10(Si,Al)16O38(OH)8 · nH2O | Mon. 2/m : B2/b |
16.16.16 | Taneyamalite | (Na,Ca)(Mn,Mg,Fe)12Si12(O,OH)44 | Tric. |
16.16.17 | Zussmanite | K(Fe,Mg,Mn)13(Si,Al)18O42(OH)14 | Trig. 3 : R3 |
16.16.18 | Coombsite | K(Mn,Fe,Mg)13(Si,Al)18O42(OH)14 | Trig. |
16.16.19 | Henritermierite | Ca3(Mn3+,Al)2(SiO4)2(OH)4 | Tet. 4/mmm (4/m 2/m 2/m) : I41/acd |
16.16.20 | Macfallite | Ca2Mn3+3(SiO4)(Si2O7)(OH)3 | Mon. |
16.16.22 | Piemontite | {Ca2}{Al2Mn3+}(Si2O7)(SiO4)O(OH) | Mon. 2/m : P21/m |
16.16.23 | Okhotskite | Ca2(Mn,Mg)(Mn3+,Al,Fe3+)2(Si2O7)(SiO4)(OH)2 · H2O | Mon. |
16.16.24 | Pumpellyite-(Mn2+) | Ca2Mn2+Al2(Si2O7)(SiO4)(OH)2 · H2O | Mon. |
16.16.25 | Piemontite-(Sr) | {CaSr}{Al2Mn3+}(Si2O7)(SiO4)O(OH) | Mon. |
Other Information
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 Ottrélite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Descloizeaux, A., Damour A.A. (1842) De l'ottrélite. Nouvelle espèce minérale. Annales des Mines: 2: 357-361.
Hutchings, W.M. (1889) On the Occurrence of Ottrelite in the Phyllites of North Cornwall. Geological Magazine (Decade III): 6(5): 214-220.
Spencer, L.J. (1898) Supplementary list of British minerals. Mineralogical Abstracts: 30: 285.
Halferdahl, L.B. (1961) Chloritoid: its composition, X-ray and optical properties, stability and occurrences. Journal of Petrology: 2: 49-135.
Fransolet, A.-M. (1978) Données nouvelles sur l'ottrélite d'Ottré, Belgique. Bulletin de la Société française de Minéralogie et de Cristallographie: 101: 548-557.
Theye, T., Fransolet, A.-M. (1994) Virtually pure ottrelite from the region of Ottré, Belgium. European journal of mineralogy: 6(4): 547-555.
Fransolet, A.-M., Theye, T. (1997) On the Ardennes chloritoids and the ottrelite term (Cambrian, Belgium-French): A comment.
Neues Jahrbuch fur Mineralogie Monatshefte: 328-331.
Internet Links for Ottrélite
mindat.org URL:
https://www.mindat.org/min-3043.html
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Localities for Ottrélite
Locality List




All localities listed without proper references should be considered as questionable.
Belgium | |
| |
| |
| Michel Bloindieau |
Hatert, F., Deliens, M., Fransolet, A.-M. & van der Meersche, E. (2002): Les minéraux de Belgique. 2ème édition, Muséum des Sciences Naturelles, Bruxelles, Ed., 304 p. | |
| Frank de Wit collection |
Descloizeux & Damour (1842): De l'Ottrelite. Nouvelle espèce minérale. Annales des Mines. 4eme Serie, Tome II, 357-361 | |
| - Fransolet, A.M., Kramm, U., Schreyer, W. (1977): Metamorphose und Magmatismus im Venn-Stavelot-Massiv, Ardennen, Fortschritte der Mineralogie, Vol. 55, Beiheft 2, pp.: 75-103 |
- Fransolet, A.M., Kramm, U., Schreyer, W. (1977): Metamorphose und Magmatismus im Venn-Stavelot-Massiv, Ardennen, Fortschritte der Mineralogie, Vol. 55, Beiheft 2, pp.: 75-103 | |
Canada | |
| Sabina, A.P. (2003): Rocks & Minerals for the collector; Kirkland Lake - Rouyn-Noranda - Val d'Or, Ontario & Quebec. GSC Misc. Report 77, 92p. |
| Sabina (2003) 66. |
| Système d'information géominière du Québec: |
| Harvard Museum of Natural History |
France | |
| R.C. Maury and P. Picot : "Conditions d'Apparition du Fer Natif dans une Enclave de Schistes Graphiteux d'une Basanite des Cévennes", Bulletin de Minéralogie, 1979, Vol. 102, N° 4, 326-332 |
Germany | |
| Geotopkataster database, Bayerisches Landesamt für Umwelt |
| Lapis 15(7/8), 59-60 (1990) |
Italy | |
| 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. |
| |
Mexico | |
| Ref.: Revista Mexicana de Ciencias Geológicas, volumen 17, número 2, p.143-153 (2000) |
Poland | |
| Lis, J., Sylwestrzak, H., 1986. Minerały Dolnego Śląska. Instytut Geologiczny, Wydawnictwa Geologiczne, Warszawa, 791 pp. |
Sweden | |
| GFF 20, 50 |
| Sandstöm, F. (2007): Västanåfeltets geologi och mineralogi. Litiofilen 24 (2): 14-38 |
| Swedish Nat.Musuem ( O.Gabrielson); Wilke, H.-J. (1997) Die Mineralien und Fundstellen von Schweden. Christian Weise Verlag, München. 200p. [p.17-18] |
| No reference listed |
UK | |
| Rastall, R.H. (1910) The Skiddaw granite and its metamorphism. Quarterly Journal of the Geological Society of London, 66, 116-141.; Cooper, M.P. and Stanley, C.J. (1990) Minerals of the English Lake District: Caldbeck Fells. Natural History Museum Publications, London, 160 pp. (referring to Rastall, 1910). |
USA | |
| Murphy, Franklin Mac (1932), Geology of a part of the Panamint Range, California Calif. Min Bureau Report 28: 347; Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 137; Pemberton, H. Earl (1983), Minerals of California; Van Nostrand Reinholt Press: 436. |
| Murdoch, Joseph & Robert W. Webb (1966), Minerals of California, Centennial Volume (1866-1966): California Division Mines & Geology Bulletin 189: 137. |
| Dana 6:1071. |
| Emerson, 1917. Geology of Mass. & Rhode Island, p.61 |
| Minerals of New Mexico 3rd ed. |
| |
| Wilson,W.F and McKenzie, B.J.,1978, Mineral Collecting Sites in North Carolina,Information Circular 24 |
| Rocks & Min.: 60: 92. |
| Rocks & Min.: 60:92. |
| Wilson,W.F and McKenZie,B.J,1978,Mineral Collecting Sites in North Carolina, Information Circular 24 |
| Rocks & Min.:60:93. |
| AmMin 12:427-436 (1927) |
Fisher, L.W. and Doll, C.G. (1927) Notes on the mineral localities of Rhode Island. American Mineralogist, 12, 427-436 | |
Miller, 1971. RI Minerals & Their Locations | |
AmMin 12:427-436 | |
| |
| Museum of Natural History, Roger Williams Park, Providence, R.I. G4196 6395 |
| U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia. | |
| Roberts, Willard Lincoln, and George Rapp, Jr. (1965), Mineralogy of the Black Hills, South Dakota School of Mines and Technology Bulletin 18. |
| Minerals of Virginia 1990 by R. V. Dietrich |
Ottré, Vielsalm, Stavelot Massif, Luxembourg, Wallonia, Belgium