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Sericite

A variety of Muscovite
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About SericiteHide

Formula:
KAl2(AlSi3O10)(OH)2
Name:
Named in 1852 by Karl/Carl List from the Greek seirος meaning "silken".
A term for a fine-grained white, pale green to oily greenish mica, mainly Muscovite (rarely Paragonite).


Unique IdentifiersHide

Mindat ID:
9252 (as Sericite)
2815 (as Muscovite)
Long-form identifier:
mindat:1:1:9252:0 (as Sericite)
mindat:1:1:2815:4 (as Muscovite)

Similar NamesHide

Cerasite (of Breithaupt)A synonym of Mendipite
Cerasite (of Kikuchi)
CerussiteA valid IMA mineral species - grandfatheredPbCO3
SorositeA valid IMA mineral speciesCu1+x(Sn,Sb)

Chemistry of SericiteHide

Mindat Formula:
KAl2(AlSi3O10)(OH)2
Element Weights:
Element% weight
O48.202 %
Si21.154 %
Al20.322 %
K9.816 %
H0.506 %

Calculated from ideal end-member formula.
O
Si
Al
K
H
Oxide Weights:
Oxide% weight
SiO245.255 %
Al2O338.398 %
K2O11.825 %
H2O4.523 %
Total100.000 %

Calculated from the ideal end-member formula.

Age distributionHide

Recorded ages:
Neoproterozoic to Quaternary : 670 Ma to 1.3 ± 0.1 Ma - based on 27 recorded ages.
Sample ages:
Sample IDRecorded ageGeologic TimeDating method
11.3 ± 0.1 MaPleistoceneAr-Ar
23.5 ± 0.9 MaPliocene
315.7 ± 0.2 MaMioceneK-Ar
420.8 ± 0.4 MaMioceneK-Ar
524.6 ± 0.3 MaOligoceneK-Ar
6137.2 ± 1.6 MaEarly/Lower CretaceousAr-Ar
7159 ± 1.5 MaJurassicK-Ar
8187.4 ± 0.3 MaEarly JurassicAr-Ar
9187.6 ± 0.4 MaEarly JurassicAr-Ar
10200 MaEarly Jurassic
11242.8 ± 0.8 MaMiddle TriassicAr-Ar
12272 to 262 MaGuadalupianK-Ar, Rb-Sr
13286.33 ± 1.2 MaCisuralianAr-Ar
14349.8 ± 3.9 MaMississippianAr-Ar
15359 ± 3.4 MaLate/Upper DevonianAr-Ar
16383.7 ± 4.7 MaMiddle DevonianAr-Ar
17386 ± 4 MaMiddle Devonian40Ar-39Ar
18412 to 403 MaEarly/Lower DevonianAr-Ar
19416 ± 4.9 MaEarly/Lower DevonianAr-Ar
20670 to 660 MaCryogenianAr-Ar
Sample references:
IDLocalityReferenceNotes
1Mutnovsky volcano, Mutnovskoe, Yelizovsky District, Kamchatka Krai, Russia
2Tirad deposit, Guinaoang, Mankayan, Benguet Province, Cordillera Administrative Region, Luzon, Philippines
3Tonopah Mining District, San Antonio Mountains, Nye County, Nevada, USA
4Oulay Mine, Lake City, Lake City Mining District, Hinsdale County, Colorado, USA
5Creede Mining District, Mineral County, Colorado, USA
6Ryabinovskoe Cu-Au deposit, Aldan, Sakha, Russia
7Vershino-Darasunskiy, Tungokochensky District, Zabaykalsky Krai, Russia
8Huangtuliang Au deposit, Zhenningpu, Chicheng County, Zhangjiakou, Hebei, China
9Hougou Mine, Xiaozhangjiakou gold field, Chicheng County, Zhangjiakou, Hebei, China
10Nikitovka Hg deposit, Gorlovka, Donetsk Oblast, Ukraine
11Nanjinshan Au Mine, Subei Co., Jiuquan, Gansu, China
12Kockbulak mine, Ohangaron District, Tashkent Region, Uzbekistan
13Akjilga Ag-Sb deposit, Bazardara ore cluster, Pamir Silver District, Gorno-Badakhshan, Tajikistan
14Karakul’skoe deposit, Yustid ore cluster, Altai Republic, Russia
15Yustid ore cluster, Tuva, Russia
16Khovu-Aksy Ni-Co deposit, Chedi-Kholsky District, Tuva, Russia
17Rara Fortuna mine, El Guaico mining district, Ciénaga del Coro District, Minas Department, Córdoba Province, Argentina
18Khovu-Aksy Ni-Co deposit, Chedi-Kholsky District, Tuva, Russia
19Abakanskoe deposit, Khakassia, Russia
20Udereiskoe, Krasnoyarsk Krai, Russia

Synonyms of SericiteHide

Other Language Names for SericiteHide

Varieties of SericiteHide

Chromium-bearing SericiteA chromium-bearing variety of sericite. See also fuchsite.

Common AssociatesHide

Associations Based on Photo Data:
76 photos of Sericite associated with QuartzSiO2
29 photos of Sericite associated with PyriteFeS2
21 photos of Sericite associated with FluoriteCaF2
13 photos of Sericite associated with AlbiteNa(AlSi3O8)
10 photos of Sericite associated with CalciteCaCO3
10 photos of Sericite associated with Epidote(CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH)
8 photos of Sericite associated with ChalcopyriteCuFeS2
8 photos of Sericite associated with SchorlNaFe2+3Al6(Si6O18)(BO3)3(OH)3(OH)
7 photos of Sericite associated with TopazAl2(SiO4)(F,OH)2
7 photos of Sericite associated with MicroclineK(AlSi3O8)

RadioactivityHide

Radioactivity:
Element % Content Activity of the element (Bq/kg) With decay products (Bq/kg) Radiation Type
Uranium (U)0.0000%00α, β, γ
Thorium (Th)0.0000%00α, β, γ
Potassium (K)9.8161%3,1123,112β, γ

The decay products of uranium and thorium build up over about a million years, so almost every natural specimen has them; they give nearly all of its gamma radiation. Young secondary uranium minerals can have lost their radium, and with it most of the gamma radiation and radon.

For comparison:

  • Banana: ~15 Bq per fruit
  • Granite: about 1,000–3,000 Bq/kg (with decay products)
  • Exempt from radiation protection rules (EU Basic Safety Standards, IAEA): 1,000 Bq/kg for each member of the uranium-238 and thorium-232 series, 10,000 Bq/kg for potassium-40; natural minerals and ores are exempt from transport rules up to 10 times these levels. This mineral is below the exemption level.

Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.

Interactive Simulator:

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Sericite in petrologyHide

Internet Links for SericiteHide

References for SericiteHide

Localities for SericiteHide

Showing 9,758 localities.

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