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Kyanite

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Formula:
Al
 
2
(SiO
 
4
)O
System:TriclinicColour:Blue, white, light gray, ...
Lustre:Vitreous, Sub-Vitreous, Greasy, PearlyHardness: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:Andalusite, Sillimanite


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Classification of Kyanite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/B.02-40
Nickel-Strunz 10th (pending) edition ID:9.AF.15

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
Dana 8th edition ID: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
Hey's CIM Ref.:15.2

15 : Silicates of Aluminum
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Occurrences of Kyanite

Geological Setting:Metamorphic rocks of moderately high pressure regional metamorphism.

Physical Properties of Kyanite

Lustre: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)
Parting:On (001)
Fracture:Splintery
Density (measured):3.53 - 3.67 g/cm3
Density (calculated):3.67 g/cm3

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)°
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
Crystal Atlas:
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Kyanite no.6 - Goldschmidt (1913-1926)

About Crystal Atlas

The mindat.org Crystal Atlas allows you to view a selection of crystal drawings of real and idealised crystal forms for this mineral and, in certain cases, 3d rotating crystal objects. The 3d models and HTML5 code are kindly provided by www.smorf.nl.

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X-Ray Powder Diffraction:
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Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data:
Data courtesy of RRUFF project at University of Arizona, used with permission.
X-Ray Powder Diffraction:
d-spacingIntensity
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

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
Maximum Birefringence:δ = 0.015 - 0.016

Chart 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

Chemical Properties of Kyanite

Formula:
Al
 
2
(SiO
 
4
)O
Simplified for copy/paste:Al2(SiO4)O
Essential elements:Al, O, Si
All elements listed in formula:Al, O, Si

Relationship of Kyanite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
9.AF.05Sillimanite
Al
 
2
(SiO
 
4
)O
9.AF.10Andalusite
Al
 
2
(SiO
 
4
)O
9.AF.10Kanonaite
Mn
3+
 
Al(SiO
 
4
)O
9.AF.20Mullite
Al
 
4+2x
Si
 
2-2x
O
 
10-x
9.AF.20Krieselite
(Al,Ga)
 
2
(GeO
 
4
)(OH)
 
2
9.AF.23Boromullite
Al
 
9
BSi
 
2
O
 
19
9.AF.25Yoderite
Mg(Al,Fe
3+
 
)
 
3
(SiO
 
4
)
 
2
O(OH)
9.AF.30Magnesiostaurolite
(Mg,Li,Fe
2+
 
)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH)
 
2
9.AF.30Staurolite
(Fe
2+
 
,Mg,Zn)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH,O)
 
2
9.AF.30Zincostaurolite
(Zn,Li,Fe
2+
 
,Mg)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH)
 
2
9.AF.35Topaz
Al
 
2
(SiO
 
4
)(F,OH)
 
2
9.AF.40Norbergite
Mg
 
3
(SiO
 
4
)(F,OH)
 
2
9.AF.45Alleghanyite
Mn
2+
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.45Chondrodite
(Mg,Fe
2+
 
)
 
5
(SiO
 
4
)
 
2
(F,OH)
 
2
9.AF.45Reinhardbraunsite
Ca
 
5
(SiO
 
4
)
 
2
(OH,F)
 
2
9.AF.45Kumtyubeite
Ca
 
5
(SiO
 
4
)
 
2
F
 
2
9.AF.45Hydroxylchondrodite
Mg
 
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.50Humite
(Mg,Fe
2+
 
)
 
7
(SiO
 
4
)
 
3
(F,OH)
 
2
9.AF.50Manganhumite
(Mn
2+
 
,Mg)
 
7
(SiO
 
4
)
 
3
(OH)
 
2
9.AF.50Unnamed (Ca-analogue of Humite)
Ca
 
7
(SiO
 
4
)
 
4
F
 
2
9.AF.55Clinohumite
Mg
 
9
(SiO
 
4
)
 
4
F
 
2
9.AF.55Sonolite
Mn
2+
9
(SiO
 
4
)
 
4
(OH,F)
 
2
9.AF.55Hydroxylclinohumite
Mg
 
9
(SiO
 
4
)
 
4
(OH)
 
2
9.AF.60Leucophoenicite
Mn
2+
7
(SiO
 
4
)
 
3
(OH)
 
2
9.AF.65Ribbeite
(Mn
2+
 
,Mg)
 
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.70Jerrygibbsite
Mn
2+
9
(SiO
 
4
)
 
4
(OH)
 
2
9.AF.75Franciscanite
Mn
2+
6
(V
5+
 
,☐)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
9.AF.75Örebroite
Mn
2+
3
(Sb
5+
 
,Fe
3+
 
)(SiO
 
4
)(O,OH)
 
3
9.AF.75Welinite
Mn
2+
6
(W
6+
 
,Mg)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
9.AF.80Ellenbergerite
Mg
 
6
(Mg,Ti,Zr,◻)
 
2
(Al,Mg)
 
6
Si
 
8
O
 
28
(OH)
 
10
9.AF.85Chloritoid
(Fe
2+
 
,Mg,Mn
2+
 
)Al
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.85Magnesiochloritoid
MgAl
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.85Ottrélite
(Mn
2+
 
,Fe
2+
 
,Mg)Al
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.90Poldervaartite
CaCa[SiO
 
3
(OH)](OH)
9.AF.90Olmiite
CaMn
2+
 
[SiO
 
3
(OH)](OH)
Related Minerals - Hey's Index Grouping:

- +
15.1Andalusite
Al
 
2
(SiO
 
4
)O
15.3Sillimanite
Al
 
2
(SiO
 
4
)O
15.4Mullite
Al
 
4+2x
Si
 
2-2x
O
 
10-x
15.5Pyrophyllite
Al
 
2
(Si
 
4
O
 
10
)(OH)
 
2
15.6Dickite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
15.7Nacrite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
15.8Kaolinite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
15.9Metahalloysite
15.10Halloysite
Al
 
2
(Si
 
2
O
 
5
)(OH)
 
4
15.11Allophane
(Al
 
2
O
 
3
)(SiO
 
2
)
 
1.3-2
· 2.5-3H
 
2
O

Other Names for Kyanite

Synonyms:
CyaniteDisteneDisthene
Other Languages:
Basque:Zianita
Croatian:Kianit
Dutch:Kyaniet
Esperanto:Kianito
Estonian:Küaniit
Finnish:Kyaniitti
French:Disthène
Sappare
German:Kyanit
Cianit
Cyanit
Disthen
Kianit
Munkrudit
Rhätizit
Riemenstein
Saphirspath
Hebrew:קיאניט
קיאנייט
Hungarian:Kianit
Italian:Cianite
Japanese:藍晶石
Polish:Dysten
Portuguese:Cianite
Russian:Кианит
Simplified Chinese:蓝晶石
Slovak:Kyanit
Spanish:Cianita
Kyanita
Munkrudita
Swedish:Kyanit
Varieties:
Chrome-KyaniteRhätizite

Other Information

Fluorescence in UV light:Not fluorescent.
Health Warning: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

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., E.C. Robertson & F. Birch (1957), Experimental determination of kyanite-sillimanite equilibrium relations at high temperatures and pressure: American Journal of Science: 255: 628-640.

Pearson, G.R. and Shaw, D.M. (1960) Trace elements in kyanite, sillimanite and andalusite. American Mineralogist: 45: 808-817.

Burnham, C.W. (1963b) Refinement of the crystal structure of kyanite. Zeitschrift für Kristallographie: 118: 337-360.

Sgarlata F. – (1965) La struttura della cianite. - Periodico di Mineralogia – Roma pp. 241-256.

Hafner, S.S. and Raymond, M. (1967) Nuclear quadrupole coupling tensors of Al27 in kyanite. American Mineralogist: 52: 1632-1642.

Chinner, G.A., J.W. Smith & C.R. Knowles (1969), Transition metal contents of Al2SiO5 polymorphs: American Journal of Science: 267A: 96-113.

G. H. Faye and E. H. Nickel (1969): On the origin of colour and pleochroism of kyanite. Can. Mineral. 10, 35-46.

Winter, J.K. and 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., and 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., and Prewitt, C.T. (1997a) Compressibility and crystal structure of kyanite at high pressure. American Mineralogist: 82: 467-474.

Pan, Y. and Fleet, M.E. (1999) Kyanite in the Western Superior Province of Ontario: implications for Archean accretionary tectonics. Canadian Mineralogist: 37: 359-373.

Rao, M.N., Chaplot, S.L., Choudhury, N., Rao, K.R., Azuah, R.T., Montfrooji, W.T., and 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., and 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., and 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., and Schreuer, J. (2001) Calculation of the elastic constants of the Al2SiO5 olymorphs andalusite, sillimanite, and kyanite. Zeitschrift für Kristallographie: 216: 67-70.

Wieczorek, A.K. and 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., and Rauch, F. (2004) Hydroxide in kyanite: a quantitative determinationof the absolute amount and calibration of the IR spectrum. American Mineralogist: 89: 998-1003.

Friedrich, A., Kunz, M., Winkler, B., and Le Bihan T. (2004) High-pressure beahvior 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., and 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. Mineral. Petrol. 107, 289-310.

Internet Links for Kyanite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Kyanite details from Handbook of Mineralogy (PDF)
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    Localities for Kyanite

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