Kyanite
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Formula:
Al2OSiO4
System:
Triclinic
Colour:
Blue, white, light gray, ...
Lustre:
Vitreous, Sub-Vitreous, Greasy, Pearly
Hardness:
5½ - 7
Name:
Named in 1789 by Abraham Gottlieb Werner from the Greek word "kyanos", meaning "blue," the common color of the species. The French spelling, "Cyanite", was commonly used by mineralogists through much of the 19th and early 20th centuries.
Polymorph of:
Common metamorphic silicate mineral.
The generally bluish colour is caused by Fe(II)-Fe(III) charge transfer (Faye and Nickel, 1969).
Visit gemdat.org for gemological information about Kyanite.
The generally bluish colour is caused by Fe(II)-Fe(III) charge transfer (Faye and Nickel, 1969).
Visit gemdat.org for gemological information about Kyanite.
Classification of Kyanite
Approved, 'Grandfathered' (first described prior to 1959)
8/B.02-40
9.AF.15
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
52.2.2c.1
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
2 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
2 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
15.2
15 : Silicates of Aluminum
15 : Silicates of Aluminum
Physical Properties of Kyanite
Vitreous, Sub-Vitreous, Greasy, Pearly
Diaphaneity (Transparency):
Transparent, Translucent
Comment:
Somewhat pearly on {100} || to the perfect cleavage
Colour:
Blue, white, light gray, green, rarely yellow, orange, pink
Streak:
Colorless
Hardness (Mohs):
5½ - 7
Comment:
5.5 parallel to [001], 7 parallel to [100]
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on (100), good on (010)
Perfect on (100), good on (010)
Parting:
On (001)
Fracture:
Splintery
Density:
3.53 - 3.67 g/cm3 (Measured) 3.67 g/cm3 (Calculated)
Optical Data of Kyanite
Type:
Biaxial (-)
RI values:
nα = 1.712 - 1.718 nβ = 1.720 - 1.725 nγ = 1.727 - 1.734
2V:
Measured: 82° to 83°, Calculated: 84°
Birefringence:
0.015
Max Birefringence:
δ = 0.015 - 0.016
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
High
Dispersion:
r > v weak
Optical Extinction:
Inclined. Z>Y>X; X perpendicular to {100}, Z' ^ c = 30° on {100}, Z' ^ c = 7° on {010}.
Pleochroism:
Weak
Comments:
X= colorless
Y= violet-blue
Z= cobalt blue
Y= violet-blue
Z= cobalt blue
Chemical Properties of Kyanite
IMA Formula:
Al2OSiO4
Elements listed in formula:
Crystallography of Kyanite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Space Group Setting:
P1
Cell Parameters:
a = 7.1262(12) Å, b = 7.8520(10) Å, c = 5.5724(10) Å
α = 89.99(2)°, β = 101.11(2)°, γ = 106.03(1)°
α = 89.99(2)°, β = 101.11(2)°, γ = 106.03(1)°
Ratio:
a:b:c = 0.908 : 1 : 0.71
Unit Cell Volume:
V 293.60 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals bladed or tabular.
Twinning:
Lamellar on (100), common
Comment:
Non-standard setting.
Crystallographic forms of Kyanite
Crystal Atlas:
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Kyanite no.6 - Goldschmidt (1913-1926)
3d models and HTML5 code kindly provided by
www.smorf.nl.
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Edge Lines | Miller Indicies | Axes
Transparency
Opaque | Translucent | Transparent
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Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation
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Edge Lines | Miller Indicies | Axes
Transparency
Opaque | Translucent | Transparent
View
Along a-axis | Along b-axis | Along c-axis | Start rotation | Stop rotation
X-Ray Powder Diffraction:
Image Loading
Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
X-Ray Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.35 | (100) |
| 3.18 | (20) |
| 2.70 | (40) |
| 2.51 | (50) |
| 2.35 | (40) |
| 2.16 | (20) |
| 1.960 | (50) |
| 1.929 | (80) |
Comments:
ICDD 11-46
Occurrences of Kyanite
Relationship of Kyanite to other Species
| 9.AF.05 | Sillimanite | Al2OSiO4 |
| 9.AF.10 | Andalusite | Al2SiO5 |
| 9.AF.10 | Kanonaite | Mn3+AlOSiO4 |
| 9.AF.20 | Mullite | Al4+2xSi2-2xO10-x (x~0.4) |
| 9.AF.20 | Krieselite | Al2GeO4(OH)2 |
| 9.AF.23 | Boromullite | Al9BSi2O19 |
| 9.AF.25 | Yoderite | (MgAl3)(MgAl)Al2O2(SiO4)4(OH)2 |
| 9.AF.30 | Magnesiostaurolite | Mg(Mg,Li)3(Al,Mg)18Si8O44(OH)4 |
| 9.AF.30 | Staurolite | Fe22+Al9Si4O23(OH) |
| 9.AF.30 | Zincostaurolite | Zn2Al9Si4O23(OH) |
| 9.AF.35 | Topaz | Al2SiO4F2 |
| 9.AF.40 | Norbergite | Mg3SiO4F2 |
| 9.AF.45 | Alleghanyite | Mn52+(SiO4)2(OH)2 |
| 9.AF.45 | Chondrodite | Mg5(SiO4)2F2 |
| 9.AF.45 | Reinhardbraunsite | Ca5(SiO4)2(OH)2 |
| 9.AF.45 | Kumtyubeite | Ca5(SiO4)2F2 |
| 9.AF.45 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 |
| 9.AF.50 | Humite | Mg7(SiO4)3(F,OH)2 |
| 9.AF.50 | Manganhumite | Mn72+(SiO4)3(OH)2 |
| 9.AF.50 | Unnamed (Ca-analogue of Humite) | Ca7(SiO4)4F2 |
| 9.AF.55 | Clinohumite | Mg9(SiO4)4F2 |
| 9.AF.55 | Sonolite | Mn92+(SiO4)4(OH)2 |
| 9.AF.55 | Hydroxylclinohumite | Mg9(SiO4)4(OH)2 |
| 9.AF.60 | Leucophoenicite | Mn72+(SiO4)3(OH)2 |
| 9.AF.65 | Ribbeite | Mn52+(SiO4)2(OH)2 |
| 9.AF.70 | Jerrygibbsite | Mn92+(SiO4)4(OH)2 |
| 9.AF.75 | Franciscanite | Mn62+V5+(SiO4)2(O,OH)6 |
| 9.AF.75 | Örebroite | Mn62+(Fe3+,Sb5+)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Welinite | (Mn4+,W)(Mn2+,Mg)(SiO4)(O,OH)3 |
| 9.AF.80 | Ellenbergerite | Mg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10 |
| 9.AF.85 | Chloritoid | Fe2+Al2OSiO4(OH)2 |
| 9.AF.85 | Magnesiochloritoid | MgAl2O(SiO4)(OH)2 |
| 9.AF.85 | Ottrélite | Mn2+Al2O(SiO4)(OH)2 |
| 9.AF.90 | Poldervaartite | Ca(Ca,Mn)(SiO3OH)(OH) |
| 9.AF.90 | Olmiite | CaMnSiO3(OH)2 |
| 15.1 | Andalusite | Al2SiO5 |
| 15.3 | Sillimanite | Al2OSiO4 |
| 15.4 | Mullite | Al4+2xSi2-2xO10-x (x~0.4) |
| 15.5 | Pyrophyllite | Al2Si4O10(OH)2 |
| 15.6 | Dickite | Al2Si2O5(OH)4 |
| 15.7 | Nacrite | Al2Si2O5(OH)4 |
| 15.8 | Kaolinite | Al2Si2O5(OH)4 |
| 15.9 | Metahalloysite | Al2(Si2O5)(OH)4 |
| 15.10 | Halloysite | Al2(Si2O5)(OH)4 |
| 15.11 | Allophane | Al2O3(SiO2)1.3-2.0 · 2.5-3.0H2O |
Other Names for Kyanite
Name in Other Languages:
Other Information
Not fluorescent.
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
Ceramics
Kyanite in petrology
An essential component of (items highlighted in red)
Common component of (items highlighted in red)
References for Kyanite
Reference List:
Klaproth, M.H. (1810) Chemische Untersuchung des Kyanits, Beiträge zur chemischen Kenntniss der Mineralkörper, Fünfter Band, Rottmann Berlin, 6-11.
Clark, S.P., Robertson, E.C., Birch, F. (1957) Experimental determination of kyanite-sillimanite equilibrium relations at high temperatures and pressure: American Journal of Science: 255: 628-640.
Pearson, G.R., Shaw, D.M. (1960) Trace elements in kyanite, sillimanite and andalusite. American Mineralogist: 45: 808-817.
Burnham, C.W. (1963) Refinement of the crystal structure of kyanite. Zeitschrift für Kristallographie: 118: 337-360.
Sgarlata, F. (1965) La struttura della cianite. Periodico di Mineralogia – Roma, 241-256.
Hafner, S.S., Raymond, M. (1967) Nuclear quadrupole coupling tensors of Al27 in kyanite. American Mineralogist: 52: 1632-1642.
Chinner, G.A., Smith, J.W., Knowles, C.R. (1969) Transition metal contents of Al2SiO5 polymorphs: American Journal of Science: 267A: 96-113.
Faye, G.H., Nickel, E.H. (1969) On the origin of colour and pleochroism of kyanite. The Canadian Mineralogist: 10: 35-46.
Winter, J.K., Ghose, S. (1979) Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs. American Mineralogist: 64: 573-586.
Kerrick, D.M. (1990) Metamorphic reactions. In D.M. Kerrick, Ed., The Al2SiO5 polymorphs. 22, 223-253. Reviews in Mineralogy. Mineralogical Society of America, Chantilly, Virginia.
Kerrick, D.M. (1990) The Al2SiO5 polymorphs, 22, 406 p. Reviews in Mineralogy, Mineralogical Society of America, Chantilly, Virginia.
Comodi, P., Zanazzi, P.F., Poli, S., Schmidt, M.W. (1997) High-pressure behavior of kyanite: decomposition of kyanite into stishovite and corundum. American Mineralogist: 82: 460-466.
Yang, H., Downs, R.T., Finger, L.W., Hazen, R.M., Prewitt, C.T. (1997) Compressibility and crystal structure of kyanite at high pressure. American Mineralogist: 82: 467-474.
Pan, Y., Fleet, M.E. (1999) Kyanite in the Western Superior Province of Ontario: implications for Archean accretionary tectonics. The Canadian Mineralogist: 37: 359-373.
Rao, M.N., Chaplot, S.L., Choudhury, N., Rao, K.R., Azuah, R.T., Montfrooji, W.T., Bennington, S.M. (1999) Lattice dynamics and inelastic neutron scattering from sillimanite and kyanite Al2SiO5. Physical Review: B60: 12061.
Dahaoui, S., Ghermani, N.E., Ghose, S., Howard, J.A.K. (2001) Electric field gradient tensors at the aluminum sites in the Al2SiO5 polymorphs from CCD high-resolution X-ray diffraction data: comparison with 27 Al NMR results. American Mineralogist: 86: 159-164.
Iglesias, M., Schwarz, K., Blaha, P., Baldomir, D. (2001) Electronic structure and electric field gradient calculations of Al2SiO5 polymorphs. Physics and Chemistry of Minerals: 28: 67-75.
Winkler, B., Hytha, M., Warren, M.C., Milman, V., Gale, J.D., Schreuer, J. (2001) Calculation of the elastic constants of the Al2SiO5 polymorphs andalusite, sillimanite, and kyanite. Zeitschrift für Kristallographie: 216: 67-70.
Wieczorek, A.K., Beran, A. (2002) Infrared spectroscopic characterization of OH defects in kyanite. 18th IMA General Meeting 1st to 6th September Edinburgh, Scotland (2002).
Bell, D., Rossman, G.R., Maldener J., Endisch, D., Rauch, F. (2004) Hydroxide in kyanite: a quantitative determination of the absolute amount and calibration of the IR spectrum. American Mineralogist: 89: 998-1003.
Friedrich, A., Kunz, M., Winkler, B., Le Bihan, T. (2004) High-pressure behavior of sillimanite and kyanite: compressibility, decomposition and indications of a new high-pressure phase. Zeitschrift für Kristallographie: 219: 324-329.
Ohuchi, F.S., Ghose, S., Engelhard, M.H., Baer, D.R. (2006) Chemical bonding and electronic structures of the Al2SiO5 polymorphs, andalusite, sillimanite, and kyanite: X-ray photoelectron- and electron energy loss spectroscopy studies. American Mineralogist: 91: 740-746.
Chadwick, K.M., Rossman, G.R. (2009) Orange kyanite from Tanzania. Gems & Gemology: 45: 146-147.
Manfred Wildner, Anton Beran, Friedrich Koller (2013) Spectroscopic characterisation and crystal field calculations of varicoloured kyanites from Loliondo, Tanzania. Mineralogy and Petrology: 107: 289-310.
Clark, S.P., Robertson, E.C., Birch, F. (1957) Experimental determination of kyanite-sillimanite equilibrium relations at high temperatures and pressure: American Journal of Science: 255: 628-640.
Pearson, G.R., Shaw, D.M. (1960) Trace elements in kyanite, sillimanite and andalusite. American Mineralogist: 45: 808-817.
Burnham, C.W. (1963) Refinement of the crystal structure of kyanite. Zeitschrift für Kristallographie: 118: 337-360.
Sgarlata, F. (1965) La struttura della cianite. Periodico di Mineralogia – Roma, 241-256.
Hafner, S.S., Raymond, M. (1967) Nuclear quadrupole coupling tensors of Al27 in kyanite. American Mineralogist: 52: 1632-1642.
Chinner, G.A., Smith, J.W., Knowles, C.R. (1969) Transition metal contents of Al2SiO5 polymorphs: American Journal of Science: 267A: 96-113.
Faye, G.H., Nickel, E.H. (1969) On the origin of colour and pleochroism of kyanite. The Canadian Mineralogist: 10: 35-46.
Winter, J.K., Ghose, S. (1979) Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs. American Mineralogist: 64: 573-586.
Kerrick, D.M. (1990) Metamorphic reactions. In D.M. Kerrick, Ed., The Al2SiO5 polymorphs. 22, 223-253. Reviews in Mineralogy. Mineralogical Society of America, Chantilly, Virginia.
Kerrick, D.M. (1990) The Al2SiO5 polymorphs, 22, 406 p. Reviews in Mineralogy, Mineralogical Society of America, Chantilly, Virginia.
Comodi, P., Zanazzi, P.F., Poli, S., Schmidt, M.W. (1997) High-pressure behavior of kyanite: decomposition of kyanite into stishovite and corundum. American Mineralogist: 82: 460-466.
Yang, H., Downs, R.T., Finger, L.W., Hazen, R.M., Prewitt, C.T. (1997) Compressibility and crystal structure of kyanite at high pressure. American Mineralogist: 82: 467-474.
Pan, Y., Fleet, M.E. (1999) Kyanite in the Western Superior Province of Ontario: implications for Archean accretionary tectonics. The Canadian Mineralogist: 37: 359-373.
Rao, M.N., Chaplot, S.L., Choudhury, N., Rao, K.R., Azuah, R.T., Montfrooji, W.T., Bennington, S.M. (1999) Lattice dynamics and inelastic neutron scattering from sillimanite and kyanite Al2SiO5. Physical Review: B60: 12061.
Dahaoui, S., Ghermani, N.E., Ghose, S., Howard, J.A.K. (2001) Electric field gradient tensors at the aluminum sites in the Al2SiO5 polymorphs from CCD high-resolution X-ray diffraction data: comparison with 27 Al NMR results. American Mineralogist: 86: 159-164.
Iglesias, M., Schwarz, K., Blaha, P., Baldomir, D. (2001) Electronic structure and electric field gradient calculations of Al2SiO5 polymorphs. Physics and Chemistry of Minerals: 28: 67-75.
Winkler, B., Hytha, M., Warren, M.C., Milman, V., Gale, J.D., Schreuer, J. (2001) Calculation of the elastic constants of the Al2SiO5 polymorphs andalusite, sillimanite, and kyanite. Zeitschrift für Kristallographie: 216: 67-70.
Wieczorek, A.K., Beran, A. (2002) Infrared spectroscopic characterization of OH defects in kyanite. 18th IMA General Meeting 1st to 6th September Edinburgh, Scotland (2002).
Bell, D., Rossman, G.R., Maldener J., Endisch, D., Rauch, F. (2004) Hydroxide in kyanite: a quantitative determination of the absolute amount and calibration of the IR spectrum. American Mineralogist: 89: 998-1003.
Friedrich, A., Kunz, M., Winkler, B., Le Bihan, T. (2004) High-pressure behavior of sillimanite and kyanite: compressibility, decomposition and indications of a new high-pressure phase. Zeitschrift für Kristallographie: 219: 324-329.
Ohuchi, F.S., Ghose, S., Engelhard, M.H., Baer, D.R. (2006) Chemical bonding and electronic structures of the Al2SiO5 polymorphs, andalusite, sillimanite, and kyanite: X-ray photoelectron- and electron energy loss spectroscopy studies. American Mineralogist: 91: 740-746.
Chadwick, K.M., Rossman, G.R. (2009) Orange kyanite from Tanzania. Gems & Gemology: 45: 146-147.
Manfred Wildner, Anton Beran, Friedrich Koller (2013) Spectroscopic characterisation and crystal field calculations of varicoloured kyanites from Loliondo, Tanzania. Mineralogy and Petrology: 107: 289-310.
Internet Links for Kyanite
mindat.org URL:
https://www.mindat.org/min-2303.html
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Central St Gotthard Massif, Leventina, Ticino, Switzerland