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.

Name Pronunciation:

Taramellite + Pronunciation

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

Diaphaneity:

Translucent to subtranslucent

Habit:

Fibrous - Crystals made up of fibers.

Hardness:

5.5 - Knife Blade

Luster:

Vitreous - Resinous

Streak:

brown

Optical Properties of Taramellite

Gladstone-Dale:

CI meas= -0.142 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.063 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1884,KPDmeas= 0.2024,KC= 0.1773
Ncalc = 1.69 - 1.74

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:

Bulk Density (Electron Density)=3.84 gm/cc
note: Specific Gravity of Taramellite =4.20 gm/cc.

Fermion Index:

Fermion Index = 0.08
Boson Index = 0.92

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Taramellite is Not Radioactive

Taramellite Classification

Dana Class:

64.03.01.01 (64)Cyclosilicates

(64.03)4-membered rings with [Si2O7] dimers

(64.03.01)Taramellite group

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

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

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

Strunz Class:

09.CE.20 09 - SILICATES (Germanates)

09.C - Cyclosilicates

09.CE -[Si4O12]8- 4-membered single rings (vierer-Einfachringe),

09.CE.20 Nagashimalite Ba4(V,Ti)4Si8B2O27Cl(O,OH)2 Pmmn 2/m 2/m 2/m

09.CE.20 Titantaramellite Ba4(Ti,Fe,Fe,Mg)4(B2Si8O27)O2ClxX=0TO1,withTi>Fe Pmmn 2/m 2/m 2/m

09.CE.20 Taramellite Ba4(Fe,Ti,Fe,Mg)4(B2Si8O27)O2Clx(x=0to1) Pmmn 2/m 2/m 2/m

Other Taramellite Information

References:

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

See Also:

Links to other databases for Taramellite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Ask about Taramellite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Taramellite Specimen Label here :

Taramellite

Ba4(Fe+++,Ti,Fe++,Mg)4(B2Si8O27)O2Clx (x=0 to 1)
Dana No: 64.03.01.01 Strunz No: 09.CE.20
Locality:

Notes: