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Talc

Formula:
Mg
 
3
Si
 
4
O
 
10
(OH)
 
2
System:TriclinicColour:Colourless, white, pale ...
Lustre:Greasy, Pearly, DullHardness:1
Name:From Arabic "talq", pure, probably alluding to the color of its powder.

Classification of Talc

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/H.09-40
Nickel-Strunz 10th (pending) edition ID:9.EC.05

9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
Dana 8th edition ID:71.2.1.3

71 : PHYLLOSILICATES Sheets of Six-Membered Rings
2 : Sheets of 6-membered rings with 2:1 layers
Hey's CIM Ref.:14.4.9

14 : Silicates not Containing Aluminum
4 : Silicates of Mg
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Occurrences of Talc

Geological Setting:Schists and steatite through hydrothermal alteration of mafic rocks. Low temperature metamorphism of siliceous dolomites.

Physical Properties of Talc

Lustre:Greasy, Pearly, Dull
Diaphaneity (Transparency):Translucent
Colour:Colourless, white, pale green, bright emrald-green to dark green, brown, gray
Streak:White
Hardness (Mohs):1
Hardness Data:Mohs hardness reference species
Tenacity:Sectile
Cleavage:Perfect
on {001}
Fracture:Sub-Conchoidal
Comment:flexible but not elastic.
Density (measured):2.58 - 2.83 g/cm3
Density (calculated):2.78 g/cm3

Crystallography of Talc

Crystal System:Triclinic
Cell Parameters:a = 5.29Å, b = 9.173Å, c = 9.46Å
α = 90.46°, β = 98.68°, γ = 90.09°
Ratio:a:b:c = 0.577 : 1 : 1.031
Unit Cell Volume:V 453.77 ų (Calculated from Unit Cell)
Z:2
Morphology:Crystals are platy, fine grained compact, massive.
X-Ray Powder Diffraction:
Image Loading

Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Talc

Type:Biaxial (-)
RI values: nα = 1.538 - 1.550 nβ = 1.589 - 1.594 nγ = 1.589 - 1.600
Maximum Birefringence:δ = 0.051

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:r > v perceptible
Pleochroism:Weak
Comments:Only visible in dark varietites

Chemical Properties of Talc

Formula:
Mg
 
3
Si
 
4
O
 
10
(OH)
 
2
Essential elements:H, Mg, O, Si
All elements listed in formula:H, Mg, O, Si
Common Impurities:Ni,Fe,Al,Ca,Na,H2O

Relationship of Talc to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
9.EC.05Minnesotaite
(Fe,Mg)
 
3
Si
 
4
O
 
10
(OH)
 
2
9.EC.05Willemseite
(Ni,Mg)
 
3
Si
 
4
O
 
10
(OH)
 
2
9.EC.10Ferripyrophyllite
Fe
 
2
Si
 
4
O
 
10
(OH)
 
2
9.EC.10Pyrophyllite
Al
 
2
Si
 
4
O
 
10
(OH)
 
2
9.EC.15Boromuscovite
KAl
 
2
[(OH)
 
2
|BSi
 
3
O
 
10
]
9.EC.15Celadonite
K(Mg,Fe
2+
 
)(Fe
3+
 
,Al)[(OH)
 
2
|Si
 
4
O
 
10
]
9.EC.15Chernykhite
(Ba,Na)(V
3+
 
,Al,Mg)
 
2
[(OH)
 
2
|(Si,Al)
 
4
O
 
10
]
9.EC.15Montdorite
(K,Na)
 
2
(Fe
2+
 
,Mn
2+
 
,Mg)
 
5
[(OH,F)
 
2
|Si
 
4
O
 
10
]
 
2
9.EC.15Muscovite
KAl
 
2
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.15Nanpingite
CsAl
 
2
[(OH,F)
 
2
|AlSi
 
3
O
 
10
]
9.EC.15Paragonite
NaAl
 
2
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.15Roscoelite
K(V,Al)
 
2
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.15Tobelite
(NH
 
4
,K)Al
 
2
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.15Aluminoceladonite
K(Mg,Fe
2+
 
)(Al,Fe
3+
 
)[(OH)
 
2
|Si
 
4
O
 
10
]
9.EC.15Chromphyllite
K(Cr,Al)
 
2
[(OH,F)
 
2
|AlSi
 
3
O
 
10
]
9.EC.15Ferro-aluminoceladonite
K(Fe
2+
 
,Mg)(Al,Fe
3+
 
)[(OH)
 
2
|Si
 
4
O
 
10
]
9.EC.15Ferroceladonite
K(Fe
2+
 
,Mg)(Fe
3+
 
,Al)[(OH)
 
2
|Si
 
4
O
 
10
]
9.EC.15Chromceladonite
K(Mg,Fe
2+
 
)(Cr,Al)[(OH)
 
2
|Si
 
4
O
 
10
]
9.EC.15Tainiolite
KLiMg
 
2
[F
 
2
|Si
 
4
O
 
10
]
9.EC.15Ganterite
(Ba,Na,K)(Al,Mg)
 
2
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Annite
KFe
2+
3
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Ephesite
NaLiAl
 
2
[(OH)
 
2
|Al
 
2
Si
 
2
O
 
10
]
9.EC.20Hendricksite
K(Zn,Mg,Mn
2+
 
)
 
3
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Masutomilite
(K,Rb)(Li,Mn
3+
 
,Al)
 
3
[(F,OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Norrishite
KLiMn
2+
2
[(OH)
 
2
|Si
 
4
O
 
10
]
9.EC.20Phlogopite
KMg
 
3
[(OH,F)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Polylithionite
KLi
 
2
Al[(F,OH)
 
2
|Si
 
4
O
 
10
]
9.EC.20Preiswerkite
NaMg
 
2
Al[(OH)
 
2
|Al
 
2
Si
 
2
O
 
10
]
9.EC.20Siderophyllite
KFe
2+
2
Al[Al
 
2
Si
 
2
O
 
10
](OH)
 
2
9.EC.20Tetra-ferriphlogopite
KMg
 
3
[(OH,F)
 
2
|(Fe
3+
 
,Al)Si
 
3
O
 
10
]
9.EC.20Wonesite
(Na,K)(Mg,fe,Al)
 
6
(Al,Si)
 
8
O
 
20
(OH,F)
 
4
9.EC.20Zinnwaldite
KLiFe
2+
 
Al[(F,OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Eastonite
KMg
 
2
Al[(OH)
 
2
|Al
 
2
Si
 
2
O
 
10
]
9.EC.20Tetraferriannite
KFe
2+
3
[(OH)
 
2
|(Fe
3+
 
,Al)Si
 
3
O
 
10
]
9.EC.20Trilithionite
K(Li,Al)
 
3
[(F,OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Fluorannite
KFe
2+
3
[(F,OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Shirokshinite
KNaMg
 
2
[F
 
2
|Si
 
4
O
 
10
]
9.EC.20Shirozulite
K(Mn
2+
 
,Mg)
 
3
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Sokolovaite
CsLi
 
2
AlSi
 
4
O
 
10
F
 
2
9.EC.20Aspidolite
NaMg
 
3
[(OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20Fluorophlogopite
KMg
 
3
[(F,OH)
 
2
|AlSi
 
3
O
 
10
]
9.EC.20UM2004-49-SiO:AlCsFHKLi
(Cs,K)(Al,Li)
 
2.6
[(Si,Al)
 
4
O
 
10
](F,OH)
 
2
9.EC.20Suhailite
(NH
 
4
)Fe
 
3
(Si
 
3
Al)O
 
10
(OH)
 
2
9.EC.20IMA2009-017
KMg
 
2.5
[Si
 
4
O
 
10
]F
 
2
9.EC.20IMA2009-006
KLi
 
2
TiSi
 
4
O
 
11
F
9.EC.25Brammallite
Na
 
0.65
Al
 
2.0
ٱAl
 
0.65
Si
 
3.35
O
 
10
(OH)
 
2
9.EC.30Margarite
CaAl
 
2
[(OH)
 
2
|Al
 
2
Si
 
2
O
 
10
]
9.EC.35Anandite
(Ba,K)(Fe
2+
 
,Mg)
 
3
[(O,OH)
 
2
|(Si,Al,Fe)
 
4
O
 
10
]
9.EC.35Bityite
CaLiAl
 
2
[(OH)
 
2
|BeAlSi
 
2
O
 
10
]
9.EC.35Clintonite
Ca(Mg,Al)
 
3
[(OH)
 
2
|Al
 
3
SiO
 
10
]
9.EC.35Kinoshitalite
(Ba,K)(Mg,Mn
2+
 
,Al)
 
3
[(OH)
 
2
|Al
 
2
Si
 
2
O
 
10
]
9.EC.35Ferrokinoshitalite
(Ba,K)(Fe
2+
 
,Mg)
 
3
[(OH,F)
 
2
|Al
 
2
Si
 
2
O
 
10
]
9.EC.35Oxykinoshitalite
(Ba,K)(Mg,Ti,Fe
3+
 
,Fe
2+
 
)
 
3
[(O,OH,F)
 
2
|(Si,Al)
 
4
O
 
10
]
9.EC.40Beidellite
(Na,Ca
 
0.5
)
 
0.3
Al
 
2
(Si,Al)
 
4
O
 
10
(OH)
 
2
·nH
 
2
O
9.EC.40Kurumsakite
(Zn,Ni,Cu)
 
8
Al
 
8
V
 
2
Si
 
5
O
 
35
·27H
 
2
O (or near)
9.EC.40Montmorillonite
(Na,Ca)
 
0.33
(Al,Mg)
 
2
Si
 
4
O
 
10
(OH)
 
2
·nH
 
2
O
9.EC.40Nontronite
Na
 
0.3
Fe
 
2
(Si,Al)
 
4
O
 
10
(OH)
 
2
·nH
 
2
O
9.EC.40Volkonskoite
Ca
 
0.3
(Cr,Mg,Fe)
 
2
(Si,Al)
 
4
O
 
10
(OH)
 
2
·4H
 
2
O
9.EC.40Yakhontovite
(Ca,Na)
 
0.5
(Cu,Fe,Mg)
 
2
Si
 
4
O
 
10
(OH)
 
2
·3H
 
2
O
9.EC.40Smectite
9.EC.45Hectorite
Na
 
0.3
(Mg,Li)
 
3
Si
 
4
O
 
10
(F,OH)
 
2
9.EC.45Saponite
Ca
 
0.25
(Mg,Fe)
 
3
(Si,Al)
 
4
O
 
10
(OH)
 
2
·nH
 
2
O
9.EC.45Sauconite
Na
 
0.3
Zn
 
3
(Si,Al)
 
4
O
 
10
(OH)
 
2
·4H
 
2
O
9.EC.45Spadaite
MgSiO
 
2
(OH)
 
2
·H
 
2
O
9.EC.45Stevensite
(Ca,Na)
 
x
Mg
 
3
Si
 
4
O
 
10
(OH)
 
2
9.EC.45Swinefordite
Li(Al,Li,Mg)
 
4
(Si,Al)
 
8
O
 
20
,(OH,F)
 
4
·xH
 
2
O
9.EC.45Zincsilite
Zn
 
3
Si
 
4
O
 
10
(OH)
 
2
·4H
 
2
O
9.EC.45Ferrosaponite
Ca
 
0.3
(Fe
2+
 
,Mg,Fe
3+
 
)
 
3
(Si,Al)
 
4
O
 
10
(OH)
 
2
·4H
 
2
O
9.EC.50Vermiculite
(Mg,Fe,Al)
 
3
(Al,Si)
 
4
O
 
10
(OH)
 
2
·4H
 
2
O
9.EC.55Baileychlore
(Zn,Fe,Al,Mg)
 
6
(Si,Al)
 
4
O
 
10
(OH)
 
8
9.EC.55Chamosite
(Fe
2+
 
,Mg)
 
5
Al[(OH)
 
8
|AlSi
 
3
O
 
10
]
9.EC.55Clinochlore
(Mg,Fe
2+
 
)
 
5
Al[(OH)
 
8
|AlSi
 
3
O
 
10
]
9.EC.55Cookeite
LiAl
 
4
(Si
 
3
Al)O
 
10
(OH)
 
8
9.EC.55Franklinfurnaceite
Ca
 
2
FeMn
 
3
MnZn
 
2
Si
 
2
O
 
10
(OH)
 
8
9.EC.55Gonyerite
(Mn,Mg)
 
5
Fe(Si
 
3
Fe)O
 
10
(OH)
 
8
9.EC.55Nimite
(Ni,Mg,Al)
 
6
(Si,Al)
 
4
O
 
10
(OH)
 
8
9.EC.55Orthochamosite
(Fe,Mg,Fe)
 
5
Al(Si
 
3
Al)O
 
10
(OH,O)
 
8
9.EC.55Pennantite
(Mn
 
5
Al)(Si
 
3
Al)O
 
10
(OH)
 
8
9.EC.55Sudoite
(Mg,Fe
2+
 
)
 
2
Al
 
3
[(OH)
 
8
|AlSi
 
3
O
 
10
]
9.EC.55Donbassite
Al
 
2
[Al
 
2.33
][Si
 
3
AlO
 
10
](OH)
 
8
9.EC.55Glagolevite
Na(Mg,Al)
 
6
[(OH,O)
 
8
|AlSi
 
3
O
 
10
]
9.EC.55Borocookeite
Li
 
1+3x
Al
 
4-x
[(BSi
 
3
)O
 
10
](OH)
 
8
[0.00 <= x <=0.33]
9.EC.60Aliettite
Ca
 
0.2
Mg
 
6
(Si,Al)
 
8
O
 
20
(OH)
 
4
·4H
 
2
O
9.EC.60Corrensite
(Mg,Fe)
 
9
(Si,Al)
 
8
O
 
20
(OH)
 
10
·nH
 
2
O
9.EC.60Dozyite
Mg
 
7
Al
 
2
[(OH)
 
12
|Al
 
2
Si
 
4
O
 
15
]
9.EC.60Hydrobiotite
9.EC.60Karpinskite
(Ni,Mg)
 
2
Si
 
2
O
 
5
(OH)
 
2
9.EC.60Kulkeite
Mg
 
8
Al(AlSi
 
7
)O
 
20
(OH)
 
10
9.EC.60Lunijianlaite
Li
 
0.7
Al
 
6.2
(Si
 
7
AlO
 
20
)(OH,O)
 
10
9.EC.60Rectorite
(Na,Ca)Al
 
4
(Si,Al)
 
8
O
 
20
(OH)
 
4
·2H
 
2
O
9.EC.60Saliotite
Li
 
0.5
Na
 
0.5
Al
 
3
Si
 
3
AlO
 
10
(OH)
 
5
9.EC.60Tosudite
9.EC.60Brinrobertsite
Na
 
0.3
Al
 
4
[(OH)
 
2
|Si
 
4
O
 
10
]
 
2
· 3.5 H
 
2
O
9.EC.65Macaulayite
(Fe,Al)
 
24
Si
 
4
O
 
43
(OH)
 
2
9.EC.70Burckhardtite
Pb
 
2
(Fe,Mn)AlTeO
 
2
Si
 
3
O
 
10
(OH)
 
2
·H
 
2
O
9.EC.75Ferrisurite
(Pb,Ca)
 
2-3
(CO
 
3
)
 
1.5-2
(OH,F)
 
0.5-1
[(Fe,Al)
 
2
Si
 
4
O
 
10
(OH)
 
2
]·nH
 
2
O
9.EC.75Surite
Pb(Pb,Ca)(CO
 
3
)
 
2
(Al,Fe,Mg)
 
2
(Si,Al)
 
4
O
 
10
(OH)
 
2
9.EC.75Niksergievite
(Ba,Ca)
 
2
(Al,Si)
 
7
O
 
10
(CO
 
3
)(OH)
 
6
·nH
 
2
O
9.EC.80Kegelite
Pb
 
12
(Zn,Fe)
 
2
Al
 
4
(SO
 
4
)
 
4
Si
 
11
O
 
38
or near
Related Minerals - Hey's Index Grouping:

- +
14.4.1Forsterite
Mg
 
2
[SiO
 
4
]
14.4.2Enstatite
Mg
 
2
[SiO
 
3
]
 
2
14.4.3Clinoenstatite
Mg
 
2
[Si
 
2
O
 
6
]
14.4.4Chrysotile
Mg
 
3
Si
 
2
O
 
5
(OH)
 
4
14.4.5Clinochrysotile
14.4.6Orthochrysotile
14.4.7Parachrysotile
14.4.8Lizardite
Mg
 
3
[(OH)
 
4
|Si
 
2
O
 
5
]
14.4.10Spadaite
MgSiO
 
2
(OH)
 
2
·H
 
2
O
14.4.11Sepiolite
Mg
 
4
Si
 
6
O
 
15
(OH)
 
2
·6H
 
2
O
14.4.12Loughlinite
Na
 
2
Mg
 
3
Si
 
6
O
 
16
·8H
 
2
O
14.4.13Eifelite
KNa
 
3
Mg
 
4
Si
 
12
O
 
30
14.4.14Stevensite
(Ca,Na)
 
x
Mg
 
3
Si
 
4
O
 
10
(OH)
 
2
14.4.15Antigorite
(Mg,Fe
2+
 
)
 
3
[(OH)
 
4
|Si
 
2
O
 
5
]
14.4.16 Magnesio-anthophyllite

Other Names for Talc

Synonyms:
AgaliteAsbestinColubrineFederweissFrench Chalk
GilsteinLardite (of Wallerius)LavezsteinLeberstein (of Haditsch & Maus)Mussolinite
OlliteTalckYalck
Other Languages:
Arabic:تلك
Basque:Talko
Bulgarian:Талк
Catalan:Talc
Croatian:Talk
Czech:Mastek
Danish:Fedtsten
Dutch:Talk
Esperanto:Talko
Finnish:Talkki
French:Talc
Craie de Briancon
Galician:Talco
German:Talk
Agalit
Mussolinit
Ollit
Hebrew:טלק
Hungarian:Zsírkő
Italian:Talco
Japanese:滑石
Latvian:Talks
Lithuanian:Talkas
Norwegian (Bokmål):Talk
Polish:Talk
Portuguese:Talco
Romanian:Talc
Russian:Тальк
Serbian (Cyrillic Script):Талк
Simplified Chinese:滑石
Slovenian:Lojevec
Spanish:Talco
Agalita
Mussolinita
Ollita
Swedish:Talk
Tamil:டால்க்
Thai:ทัลก์
Turkish:Talk
Ukrainian:Тальк
Varieties:
BeaconiteChromian TalcPolyphant StonePseudoliteSteatite

Other Information

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:Filler in paints, rubber. In cosmetics and as a lubricating dusting powder.

References for Talc

Reference List:Rayner, J.H., & G. Brown, The crystal structure of talc: Clays and Clay Minerals: 21: 103-114.

Avgustinik, A.I. and Vigderganz, V.S. (1948) Properties of talc during heating. Ogneupory: 13: 218-227.

Krönert, W., Schwiete, H.E., and Suchow, A. (1964a) Das thermische Verhalten von Speckstein und die Stabilität der Magnesiummetasilikat-Modifikationen. Ziegelindustrie: 17: 364-369.

Krönert, W., Schwiete, H.E., and Suchow, A. (1964b) Über das thermische Verhalten von Speckstein und die Stabilität der MgSiO3-Modifikationen. Naturwissenschaften: 51: 85-86.

Bošković, S.B., Gašić, M.Č., Nikolić, V.S., and Ristić, M.M. (1968) The structural changes of talc during heating. Proceedings of the British Ceramic Society: 10: 1-12.

Perdikatsis B., Burzlaff H. (1981), Zeitschrift für Kristallographie: 156: 177.

Wesolowski, M. (1984) Thermal decomposition of talc: a review. Thermochimica Acta: 78: 395-421.

Pawley, A.R., Redfern, S.A.T., and Wood, B.J. (1995) Thermal expansivities and compressibilities of hydrous phases in the system MgO-SiO2-H2O: talc, phase A, and 10-Å Phase. Contributions to Mineralogy and Petrology: 122: 301-307.

Ferrage, E., Martin, F., Petit, S., Pejo-Soucaille, S., Micoud,P., Fourty, G., Ferret, J., Salvi, S., de Parseval, P., and Fortune, J.P. (2003) Evaluation of talc morphology using FTIR and H/D substitution. Clay Minerals: 38: 141-150.

Petit, S., Martin, F., Wieqiora, A., de Parseval, P., and Decarreau, A. (2004) Crystal-chemistry of talc: A near infrared (NIR) spectroscopy study. American Mineralogist: 89: 319-326.

Zhang, M., Hui, Q., Lou, X.-J., Redfern, A.T., Salje, E.K.H., and Tarantino, S.C. (2006) Dehydroxylation, proton migration, and structural changes in heated talc: An infrared spectroscopic study: American Mineralogist: 91: 816-825.

Internet Links for Talc

Search Engines:
  • Look for Talc on Google
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  • External Links:
  • Look for Talc on Webmineral
  • Look for Talc on Athena Mineralogy
  • Look for Talc on Wikipedia
  • Look for Talc on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Talc in the Natural History Museum (London) online catalogue
  • Talc details from Handbook of Mineralogy (PDF)
  • Mineral Dealers:
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    Localities for Talc

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