Tamaite Mineral Data

Tamaite Mineral Data

General Tamaite Information

Chemical Formula:

(Ca,K,Ba,Na)3-4Mn24(Si,Al)40(O,OH)112·21(H2O)

Composition:

Molecular Weight = 4,822.34 gm

Potassium 0.69 % K 0.83 % K₂O

Barium 1.85 % Ba 2.07 % BaO

Sodium 0.26 % Na 0.35 % Na₂O

Calcium 1.37 % Ca 1.92 % CaO

Manganese 27.34 % Mn 35.30 % MnO

Aluminum 4.03 % Al 7.61 % Al₂O₃

Silicon 19.10 % Si 40.87 % SiO₂

Hydrogen 1.23 % H 10.96 % H₂O

Oxygen 44.13 % O

______ ______

100.00 % 99.92 % = TOTAL OXIDE

Empirical Formula:

Ca_1.65K_0.85Ba_0.65Na_0.55Mn²⁺₂₄Si_32.8Al_7.2O_95.3(OH)_16.7·21(H₂O)

Environment:

Veinlets in weakly metamorphosed Mn ore deposit. Ca analog of Ganophyllite.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Shiromaru mine, Okutama, Tama district, about 60 km from Tokyo, Japan. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

IMA1999-011

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Tamaite Crystallography

Axial Ratios:

a:b:c =0.6137:1:0.935

Cell Dimensions:

a = 16.64, b = 27.11, c = 25.35, Z = 4; beta = 98.74° V = 11,302.86 Den(Calc)= 2.83

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 12.6(1), 2.69(0.9), 2.46(0.75),2.6(0.75), 2.84(0.75), 3.13(0.75), 3.46(0.5),

Crystal Structure:

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Hughes J M , Rakovan J F , Bracco R , Gunter M E , American Mineralogist , 88 (2003) p.1324-1330, The atomic arrangemetn of the ganophyllite-group modulated layer silicates as, determined from the orthorhombic dimorph of tamaite, with the elusive 16.8 A, ganophyllite-group superstructure revealed, Note: signs of the y-coordinates for O24 and O25 have been changed

Physical Properties of Tamaite

Cleavage:

[001] Perfect

Color:

Colorless, Pale yellowish brown.

Density:

2.85

Diaphaniety:

Transparent

Habit:

Micaceous - Platy texture with "flexible" plates.

Habit:

Platy - Sheet forms (e.g. micas).

Hardness:

4 - Fluorite

Luster:

Vitreous - Pearly

Streak:

white

Optical Properties of Tamaite

Gladstone-Dale:

CI meas= 0.008 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2163,KPDmeas= 0.2147,KC= 0.2166

Optical Data:

Biaxial (-), b=1.612

Calculated Properties of Tamaite

Electron Density:

r_electron=2.78 gm/cc
note: r_Tamaite=2.83 gm/cc.

Fermion Index

Fermion Index = 0.01245
Boson Index = 0.98755

Photoelectric:

PE_Tamaite= 15.58 barns/electron
U=PE_Tamaite x r_electron= 43.28 barns/cc.

Radioactivity:

GRapi = 9.77 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Tamaite - barely detectable

Tamaite Classification

Dana Class:

74.1.2.3 (74)Phyllosilicate Modulated Layers

(74.1)with joined islands

(74.1.2)Ganophyllite group

74.1.2.1 Ganophyllite (K,Na)2(Mn,Al,Mg)8(Si,Al)12O29(OH)7·8-9(H2O) A2/a 2/m

74.1.2.2 Eggletonite Na2Mn8[Si11AlO29](OH)7·11(H2O) Ia or I2/a Mono

74.1.2.3 Tamaite ! (Ca,K,Ba,Na)3-4Mn24(Si,Al)40(O,OH)112·21(H2O) P 2₁/a 2/m

Strunz Class:

VIII/H.17-75 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like layered silicates with [Si4O10]4- and related groups

VIII/H.17 - Stilpnomelane series

VIII/H.17-10 Bannisterite KCa(Mn,Fe,Zn,Mg)21(Si,Al)32O76(OH)16·4-12(H2O) A2/a 2/m

VIII/H.17-20 Bariumbannisterite* (K,H3O)(Ba,Ca)(Mn,Fe,Mg)21(Si,Al)32O80(O,OH)16·4-12(H2O) Mono

VIII/H.17-30 Lennilenapeite K6-7(Mg,Mn,Fe,Fe,Zn)48(Si,Al)72(O,OH)216·16(H2O) Unk (pseudo-HEX) Tri

VIII/H.17-40 Stilpnomelane K(Fe,Mg,Fe)8(Si,Al)12(O,OH)27·n(H2O) P1 1

VIII/H.17-45 Franklinphilite (K,Na)4(Mn,Mg,Zn)48(Si,Al)72(O,OH)216·6(H2O) pseudo-HEX P1 or P1 Tri

VIII/H.17-50 Parsettensite (K,Na,Ca)(Mn,Al)7Si8O20(OH)8·2(H2O)(?) C 2/m 2/m

VIII/H.17-60 Ganophyllite (K,Na)2(Mn,Al,Mg)8(Si,Al)12O29(OH)7·8-9(H2O) A2/a 2/m

VIII/H.17-70 Eggletonite Na2Mn8[Si11AlO29](OH)7·11(H2O) Ia or I2/a Mono

VIII/H.17-75 Tamaite (Ca,K,Ba,Na)3-4Mn24(Si,Al)40(O,OH)112·21(H2O) P 2₁/a 2/m

VIII/H.17-80 Ekmanite? (Fe,Mg,Mn,Fe)3(Si,Al)4O10(OH)2·2(H2O) Unk Ortho

Other Tamaite Information

References:

NAME( AmMin, vol 86, p769) PHYS. PROP.(AmMin, vol 86, p769) OPTIC PROP.(AmMin, vol 86, p769)

See Also:

Links to other databases for Tamaite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 -Google Images 4 -Google Scholar 5 -MinDAT 6 -MinMax(Deutsch) 7 -MinMax(English) 8 -Mineralienatlas (Deutsch) 9 -QUT Mineral Atlas

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Tamaite

(Ca,K,Ba,Na)3-4Mn24(Si,Al)40(O,OH)112·21(H2O)
Dana No: 74.1.2.3 Strunz No: VIII/H.17-75
Locality:

Notes: