Kyanite
A valid IMA mineral species - grandfathered
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About Kyanite
Formula:
Al2(SiO4)O
Colour:
Blue, white, light gray, green, rarely yellow, orange, pink
Lustre:
Vitreous, Sub-Vitreous, Greasy, Pearly
Hardness:
5½ - 7
Specific Gravity:
3.53 - 3.67
Crystal System:
Triclinic
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).
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.
Unique Identifiers
Mindat ID:
2303
Long-form identifier:
mindat:1:1:2303:6
GUID
(UUID V4):
(UUID V4):
f6114d65-10f7-41b0-82d6-81b34d6671d7
IMA Classification of Kyanite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Al2OSiO4
Classification of Kyanite
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
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Symbol | Source | Reference |
---|---|---|
Ky | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Ky | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
Ky | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
Ky | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
Ky | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Kyanite
Vitreous, Sub-Vitreous, Greasy, Pearly
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:
5½ - 7 on Mohs scale
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.
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:
Not Visible
Comments:
Pleochroism is not usually observed in kyanite of standard thickness. However, in thick sections, the pleochroism scheme may be:
X= colorless
Y= violet-blue
Z= cobalt blue
X= colorless
Y= violet-blue
Z= cobalt blue
Chemistry of Kyanite
Mindat Formula:
Al2(SiO4)O
Elements listed:
Crystallography of Kyanite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
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 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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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
---|---|---|---|---|---|---|---|
0000733 | Kyanite | Winter J K, Ghose S (1979) Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs American Mineralogist 64 573-586 | 1979 | 0 | 298 | ||
0000734 | Kyanite | Winter J K, Ghose S (1979) Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs American Mineralogist 64 573-586 | 1979 | 0 | 673 | ||
0000735 | Kyanite | Winter J K, Ghose S (1979) Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs American Mineralogist 64 573-586 | 1979 | 0 | 873 | ||
0001887 | Kyanite | Comodi P, Zanazzi P F, Poli S, Schmidt M W (1997) High-pressure behavior of kyanite: Compressibility and structural deformation American Mineralogist 82 452-459 | 1997 | 0.0001 | 293 | ||
0001888 | Kyanite | Comodi P, Zanazzi P F, Poli S, Schmidt M W (1997) High-pressure behavior of kyanite: Compressibility and structural deformation American Mineralogist 82 452-459 | 1997 | 0.01 | 293 | ||
0001889 | Kyanite | Comodi P, Zanazzi P F, Poli S, Schmidt M W (1997) High-pressure behavior of kyanite: Compressibility and structural deformation American Mineralogist 82 452-459 | 1997 | 2.54 | 293 | ||
0001890 | Kyanite | Comodi P, Zanazzi P F, Poli S, Schmidt M W (1997) High-pressure behavior of kyanite: Compressibility and structural deformation American Mineralogist 82 452-459 | 1997 | 3.7 | 293 | ||
0001891 | Kyanite | Comodi P, Zanazzi P F, Poli S, Schmidt M W (1997) High-pressure behavior of kyanite: Compressibility and structural deformation American Mineralogist 82 452-459 | 1997 | 4.7 | 293 | ||
0001892 | Kyanite | Yang H, Downs R T, Finger L W, Hazen R M, Prewitt C T (1997) Compressibility and crystal structure of kyanite, Al2SiO5, at high pressure American Mineralogist 82 467-474 | 1997 | 0 | 293 | ||
0001893 | Kyanite | Yang H, Downs R T, Finger L W, Hazen R M, Prewitt C T (1997) Compressibility and crystal structure of kyanite, Al2SiO5, at high pressure American Mineralogist 82 467-474 | 1997 | 1.35 | 293 | ||
0001894 | Kyanite | Yang H, Downs R T, Finger L W, Hazen R M, Prewitt C T (1997) Compressibility and crystal structure of kyanite, Al2SiO5, at high pressure American Mineralogist 82 467-474 | 1997 | 2.54 | 293 | ||
0001895 | Kyanite | Yang H, Downs R T, Finger L W, Hazen R M, Prewitt C T (1997) Compressibility and crystal structure of kyanite, Al2SiO5, at high pressure American Mineralogist 82 467-474 | 1997 | 3.73 | 293 | ||
0001896 | Kyanite | Yang H, Downs R T, Finger L W, Hazen R M, Prewitt C T (1997) Compressibility and crystal structure of kyanite, Al2SiO5, at high pressure American Mineralogist 82 467-474 | 1997 | 4.56 | 293 | ||
0017903 | Kyanite | Naray-Szabo S, Taylor W, Jackson W (1929) The Structure of Cyanite _cod_database_code 1010987 Zeitschrift fur Kristallographie 71 117-130 | 1929 | 0 | 293 | ||
0016632 | Kyanite | de Rango C, Tsoucaris G, Zelwer C, Devaux J (1966) Comparaison de deux affinements de la structure de la cyanite _cod_database_code 1008755 Bulletin de la Societe Francaise de Mineralogie et de Cristallographie 89 419-424 | 1966 | 0 | 293 | ||
0016636 | Kyanite | de Rango C, Tsoucaris G, Zelwer C, Devaux J (1966) Comparaison de deux affinements de la structure de la cyanite _cod_database_code 1008759 Bulletin de la Societe Francaise de Mineralogie et de Cristallographie 89 419-424 | 1966 | 0 | 293 | ||
0017255 | Kyanite | Taylor W, Jackson W (1928) The structure of cyanite, Al2SiO5 _cod_database_code 1010329 Proceedings of the Royal Society of London 119 132-146 | 1928 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
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Radiation - Copper Kα
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
6.7 Å | (3) |
5.89 Å | (3) |
4.42 Å | (5) |
4.30 Å | (25) |
3.77 Å | (20) |
3.44 Å | (5) |
3.35 Å | (65) |
3.18 Å | (100) |
3.02 Å | (15) |
2.947 Å | (20) |
2.782 Å | (1) |
2.727 Å | (9) |
2.699 Å | (25) |
2.694 Å | (25) |
2.612 Å | (7) |
2.602 Å | (3) |
2.520 Å | (30) |
2.509 Å | (20) |
2.460 Å | (5) |
2.366 Å | (1) |
2.361 Å | (1) |
2.355 Å | (30) |
2.350 Å | (30) |
2.31 Å | (20) |
2.272 Å | (11) |
2.233 Å | (9) |
2.214 Å | (15) |
2.181 Å | (7) |
2.168 Å | (5) |
2.163 Å | (20) |
2.151 Å | (3) |
2.006 Å | (7) |
1.973 Å | (3) |
1.962 Å | (55) |
1.935 Å | (50) |
1.930 Å | (50) |
1.883 Å | (5) |
1.865 Å | (3) |
1.846 Å | (3) |
1.820 Å | (1) |
1.791 Å | (1) |
1.764 Å | (11) |
1.754 Å | (1) |
1.747 Å | (3) |
1.676 Å | (9) |
1.650 Å | (3) |
1.621 Å | (7) |
1.606 Å | (3) |
1.593 Å | (20) |
1.573 Å | (3) |
Comments:
ICDD 11-46, See also ICDD 11-46a major lines at 1.475 (15), 1.392 (25), and 1.377 (75).
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Near-surface Processes | |
26 : Hadean detrital minerals | |
Stage 4b: Highly evolved igneous rocks | >3.0 |
36 : Carbonatites, kimberlites, and related igneous rocks | |
Stage 5: Initiation of plate tectonics | <3.5-2.5 |
39 : High-𝑃 metamorphism (blueschist, eclogite, ultrahigh 𝑃 facies) | |
40 : Regional metamorphism (greenschist, amphibolite, granulite facies) |
Geological Setting:
Metamorphic rocks of moderately high-pressure regional metamorphism.
Synonyms of Kyanite
Other Language Names for Kyanite
Varieties of Kyanite
Rhätizite | A white to gray-white variety of Kyanite. |
Common Associates
Associated Minerals Based on Photo Data:
372 photos of Kyanite associated with Quartz | SiO2 |
104 photos of Kyanite associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
98 photos of Kyanite associated with Staurolite | Fe2+2Al9Si4O23(OH) |
51 photos of Kyanite associated with Rutile | TiO2 |
51 photos of Kyanite associated with Andalusite | Al2(SiO4)O |
46 photos of Kyanite associated with Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
38 photos of Kyanite associated with Garnet Group | X3Z2(SiO4)3 |
36 photos of Kyanite associated with Corundum | Al2O3 |
34 photos of Kyanite associated with Fuchsite | K(Al,Cr)3Si3O10(OH)2 |
32 photos of Kyanite associated with Pyrite | FeS2 |
Related Minerals - Strunz-mindat Grouping
9.AF. | Chegemite | Ca7(SiO4)3(OH)2 |
9.AF. | Barwoodite | Mn2+6Nb5+(SiO4)2O3(OH)3 |
9.AF. | Jingwenite-(Y) | YAlV4+(SiO4)O2(OH)2 |
9.AF.05 | Sillimanite | Al2(SiO4)O |
9.AF.05 | Xenolite | Al10Si8O31 |
9.AF.10 | Andalusite | Al2(SiO4)O |
9.AF.10 | Kanonaite | Mn3+Al(SiO4)O |
9.AF.20 | Mullite | Al4+2xSi2-2xO10-x |
9.AF.20 | Krieselite | Al2(GeO4)F2 |
9.AF.23 | Boromullite | Al9BSi2O19 |
9.AF.25 | Yoderite | Mg(Al,Fe3+)3(SiO4)2O(OH) |
9.AF.30 | Magnesiostaurolite | Mg(Mg,Li)3(Al,Mg)18Si8O44(OH)4 |
9.AF.30 | Staurolite | Fe2+2Al9Si4O23(OH) |
9.AF.30 | Zincostaurolite | Zn2Al9Si4O23(OH) |
9.AF.35 | Topaz | Al2(SiO4)(F,OH)2 |
9.AF.40 | Norbergite | Mg3(SiO4)F2 |
9.AF.45 | Alleghanyite | Mn2+5(SiO4)2(OH)2 |
9.AF.45 | Chondrodite | Mg5(SiO4)2F2 |
9.AF.45 | Reinhardbraunsite | Ca5(SiO4)2(OH,F)2 |
9.AF.45 | Kumtyubeite | Ca5(SiO4)2F2 |
9.AF.45 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 |
9.AF.50 | Humite | Mg7(SiO4)3F2 |
9.AF.50 | Manganhumite | (Mn2+,Mg)7(SiO4)3(OH)2 |
9.AF.50 | Unnamed (Ca-analogue of Humite) | Ca7(SiO4)4F2 |
9.AF.50 | Fluorchegemite | Ca7(SiO4)3F2 |
9.AF.50 | Unnamed (OH-analogue of humite) | Mg7(SiO4)3(OH)2 |
9.AF.55 | Clinohumite | Mg9(SiO4)4F2 |
9.AF.55 | Sonolite | Mn2+9(SiO4)4(OH)2 |
9.AF.55 | Hydroxylclinohumite | Mg9(SiO4)4(OH)2 |
9.AF.60 | Leucophoenicite | Mn2+7(SiO4)3(OH)2 |
9.AF.65 | Ribbeite | Mn2+5(SiO4)2(OH)2 |
9.AF.70 | Jerrygibbsite | Mn2+9(SiO4)4(OH)2 |
9.AF.75 | Franciscanite | Mn2+6(V5+,◻)2(SiO4)2(O,OH)6 |
9.AF.75 | Örebroite | Mn2+3(Sb5+,Fe3+)(SiO4)(O,OH)3 |
9.AF.75 | Welinite | Mn2+6(W6+,Mg)2(SiO4)2(O,OH)6 |
9.AF.75 | Scorticoite | Mn6(Sb,◻)Σ2(SiO4)2O3(OH)3 |
9.AF.80 | Ellenbergerite | Mg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10 |
9.AF.85 | Chloritoid | (Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2 |
9.AF.85 | Magnesiochloritoid | MgAl2(SiO4)O(OH)2 |
9.AF.85 | Ottrélite | (Mn2+,Fe2+,Mg)Al2(SiO4)O(OH)2 |
9.AF.90 | Poldervaartite | CaCa[SiO3(OH)](OH) |
9.AF.90 | Olmiite | CaMn2+[SiO3(OH)](OH) |
9.AF.95 | Pilawite-(Y) | Ca2Y2Al4(SiO4)4O2(OH)2 |
Fluorescence of Kyanite
Not usually fluorescent. Weak pink-red fluorescence under longwave reported at Thomaston Dam, Connecticut (Don Swenson, pers. com., 2017). Robbins (1994) indicated that some kyanite fluoresces: "From Pfitsch in the Tyrol, Austria, colorless blades of kyan
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.
Industrial Uses:
Ceramics
Kyanite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Kyanite
mindat.org URL:
https://www.mindat.org/min-2303.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Kyanite
Reference List:
Faye, G. H., Nickel, E. H. (1969) On the origin of colour and pleochroism of kyanite. The Canadian Mineralogist, 10 (1) 35-46
Localities for Kyanite
Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and 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 (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
Central St Gotthard Massif, Leventina, Ticino, Switzerland