Taramellite Mineral Data

Taramellite Mineral Data +

General Taramellite Information

Chemical Formula:

Ba4(Fe+++,Ti,Fe++,Mg)4(B2Si8O27)O2Clx (x=0 to 1)

Composition:

Molecular Weight = 1,525.66 gm

Barium 30.60 % Ba 34.17 % BaO

Magnesium 0.16 % Mg 0.26 % MgO

Titanium 1.88 % Ti 3.14 % TiO₂

Iron 11.71 % Fe 13.66 % FeO / 1.57 % Fe₂O₃

Silicon 14.36 % Si 30.72 % SiO₂

Boron 1.56 % B 5.02 % B₂O₃

Lead 8.15 % Pb 8.78 % PbO

Chlorine 1.16 % Cl 1.16 % Cl

- % Cl -0.26 % -O=Cl₂

Oxygen 30.41 % O

______ ______

100.00 % 98.22 % = TOTAL OXIDE

Empirical Formula:

Ba_3.4Pb_0.6Fe²⁺_2.9Ti_0.6Fe³⁺_0.3Mg_0.1B_2.2Si_7.8O₂₉Cl_0.5

Environment:

A contact-metamorphic mineral.

IMA Status:

Valid Species (Pre-IMA) 1908

Locality:

Candoglia, in the Toce Valley, Piedmont, Italy Link to MinDat.org Location Data.

Name Origin:

Named for Torquato Taramelli (1845-1922), Italian geologist.

Synonym:

ICSD 100266

PDF 17-479

Taramellite Image

Images:

Taramellite

Comments: Dark brown crystalline taramellite.
Location: Candoglia, Domo d'Ossola, Val Toce, Piedmonte, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Taramellite Crystallography

Axial Ratios:

a:b:c =0.8704:1:0.5123

Cell Dimensions:

a = 12.125, b = 13.929, c = 7.136, Z = 2; V = 1,205.19 Den(Calc)= 4.20

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pmmn

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

By Intensity(I/I_o): 3.01(1), 2.584(0.55), 3.83(0.5),

Crystal Structure:

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Mazzi F , Rossi G , American Mineralogist , 65 (1980) p.123-128, The crystal structure of taramellite, Locality: Candoglia, Italy

View Additional jPOWD Structure files for Taramellite
[1]

Physical Properties of Taramellite

Cleavage:

[010] Perfect

Color:

Reddish brown, Bronze purple, Brownish violet.

Density:

3.9 - 3.92, Average = 3.91

Diaphaniety:

Translucent to subtranslucent

Habit:

Fibrous - Crystals made up of fibers.

Hardness:

5.5 - Knife Blade

Luster:

Vitreous - Resinous

Streak:

brown

Optical Properties of Taramellite

Optical Data:

Biaxial (+), a=1.77, b=1.774, g=1.83, bire=0.0600, 2V(Calc)=32, 2V(Meas)=77. Dispersion r > v distinct.

Pleochroism (x):

flesh red or pale pinkish.

Pleochroism (y):

flesh red or pale pinkish.

Pleochroism (z):

black or nearly opaque.

Calculated Properties of Taramellite

Electron Density:

r_electron=3.84 gm/cc
note: r_Taramellite=4.20 gm/cc.

Fermion Index

Fermion Index = 0.08758
Boson Index = 0.91242

Photoelectric:

PE_Taramellite= 275.56 barns/electron
U=PE_Taramellite x r_electron=1,058.84 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Taramellite is Not Radioactive

Taramellite Classification

Dana Class:

64.3.1.1 (64)Cyclosilicate Rings with Other Anions and Insular Silicate Groups

(64.3)4-membered rings with [Si2O7] dimers

(64.3.1)Taramellite group

64.3.1.1 Taramellite Ba4(Fe,Ti,Fe,Mg)4(B2Si8O27)O2Clx(x=0to1) Pmmn 2/m 2/m 2/m

64.3.1.2 Titantaramellite Ba4(Ti,Fe,Fe,Mg)4(B2Si8O27)O2ClxX=0TO1,withTi>Fe Pmmn 2/m 2/m 2/m

64.3.1.3 Nagashimalite Ba4(V,Ti)4Si8B2O27Cl(O,OH)2 Pmmn 2/m 2/m 2/m

Strunz Class:

VIII/E.08-30 VIII - Silicates

VIII/E - Cyklosilicates, quadruplet rings [Si4O11]8-

VIII/E.08 - Joaquinite group, Baotite - Orthojoaquinite-(Ce) series

VIII/E.08-05 Verplanckite Ba2(Mn,Ti,Fe)2Si2O6(O,OH,Cl,F)2·3(H2O) P 6/mmm 6/m 2/m 2/m

VIII/E.08-10 Baotite Ba4(Ti,Nb)8Si4O28Cl I 4₁/a 4/m

VIII/E.08-15 Cerchiaraite! Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26 I 4/mmm 4/m 2/m 2/m

VIII/E.08-20 Titantaramellite Ba4(Ti,Fe,Fe,Mg)4(B2Si8O27)O2ClxX=0TO1,withTi>Fe Pmmn 2/m 2/m 2/m

VIII/E.08-30 Taramellite Ba4(Fe,Ti,Fe,Mg)4(B2Si8O27)O2Clx(x=0to1) Pmmn 2/m 2/m 2/m

VIII/E.08-40 Nagashimalite Ba4(V,Ti)4Si8B2O27Cl(O,OH)2 Pmmn 2/m 2/m 2/m

VIII/E.08-50 Strontiojoaquinite (Na,Fe)2Ba2Sr2Ti2[Si4O12]2(O,OH)2·(H2O) C 2 2

VIII/E.08-60 Strontio-orthojoaquinite (Na,Fe)2Ba2Sr2Ti2[Si4O12]2(O,OH)2·(H2O) Pbcm or Pbc2 Ortho

VIII/E.08-70 Bario-orthojoaquinite Fe2(Ba,Sr)4Ti2[Si4O12]O2·(H2O) Ccmm or Ccm2 Ortho

VIII/E.08-80 Joaquinite-(Ce) NaFeBa2Ce2(Ti,Nb)2[Si4O12]2O2(OH,F)·(H2O) C 2 2

VIII/E.08-89 Orthojoaquinite-(La)! Ba2Na(La,Ce)2FeTi2Si8O26(OH,O,F)·H2O Ccmm 2/m 2/m 2/m

VIII/E.08-90 Orthojoaquinite-(Ce) NaFeBa2Ce2Ti2[Si4O12]2O2(OH)·(H2O) Ccmm or Ccm21 Ortho

Other Taramellite Information

References:

NAME( Ford32) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

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Taramellite

Ba4(Fe+++,Ti,Fe++,Mg)4(B2Si8O27)O2Clx (x=0 to 1)
Dana No: 64.3.1.1 Strunz No: VIII/E.08-30
Locality:

Notes: