Cerchiaraite Mineral Data

General Cerchiaraite Information

Chemical Formula:

Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26

Composition:

Molecular Weight = 1,398.66 gm

Barium 39.27 % Ba 43.85 % BaO

Manganese 13.35 % Mn 17.24 % MnO

Aluminum 0.58 % Al 1.09 % Al₂O₃

Iron 1.60 % Fe 2.05 % FeO

Silicon 12.05 % Si 25.77 % SiO₂

Hydrogen 0.52 % H 4.64 % H₂O

Chlorine 3.80 % Cl 3.80 % Cl

- % Cl -0.86 % -O=Cl₂

Oxygen 28.83 % O

______ ______

100.00 % 97.60 % = TOTAL OXIDE

Empirical Formula:

Ba₄Mn²⁺_3.4Fe²⁺_0.4Al_0.3Si₆O₁₈(OH)_7.2Cl_1.5

Environment:

Individual grains in fractures.

IMA Status:

Approved IMA 1999 (Dana # Added)

Locality:

Cerchiara manganese (braunite) mine, Val di Vara, eastern Liguria, Italy. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Synonym:

IMA1999-012

Cerchiaraite Image

Images:

Cerchiaraite

Comments: Green aggregates of cerchiaraite on matrix.
Location: Cerchiara Mine, Near Faggiona, Val di Vara, Eastern Liguria, Italy. Scale: Specimen Size 13x7x6 mm.
© Sergey Vasiliev / Systematic Mineralogy

Cerchiaraite Crystallography

Axial Ratios:

a:c = 1:0.43095

Cell Dimensions:

a = 14.215, c = 6.126, Z = 2; V = 1,237.86 Den(Calc)= 3.75

Crystal System:

Tetragonal - Ditetragonal DipyramidalH-M Symbol (4/m 2/m 2/m) Space Group: I 4/mmm

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

By Intensity(I/I_o): 3.011(1)(411), 10.15(0.88)(110), 3.319(0.75)(321),2.619(0.74)(222), 2.577(0.62)(501), 5.63(0.5)(101), 4.417(0.49)(211),

Crystal Structure:

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Basso R , Lucchetti G , Zefiro L , Palenzona A , Neues Jahrbuch fur Mineralogie, Monatshefte , 2000 (2000) p.373-384, Cerchiaraite, a new natural Ba-Mn-mixed-anion silicate chloride from, the Cerchiara mine, northern Apennines, Italy, Locality: Cerchiara mine, Va di Vara, northern Apennines, Italy

Physical Properties of Cerchiaraite

Cleavage:

None

Color:

Deep green.

Diaphaneity:

Transparent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)

Hardness:

4-5 - Fluorite-Apatite

Luster:

Vitreous (Glassy)

Streak:

pale green

Optical Properties of Cerchiaraite

Gladstone-Dale:

CI calc= -0.134 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2013,KC= 0.1776
Ncalc = 1.67

Optical Data:

Uniaxial (+), w=1.745, e=1.765, bire=0.0200.

Calculated Properties of Cerchiaraite

Electron Density:

Bulk Density (Electron Density)=3.44 gm/cc
note: Specific Gravity of Cerchiaraite =3.75 gm/cc.

Fermion Index:

Fermion Index = 0.07
Boson Index = 0.93

Photoelectric:

PE_Cerchiaraite= 176.49 barns/electron
U=PE_Cerchiaraite x rElectron Density= 607.19 barns/cc.

Radioactivity:

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

Cerchiaraite Classification

Dana Class:

62.01.01.02 (62)Cyclosilicate Eight-Membered Rings

(62.01)with 8-memebered and larger rings

(62.01.01)Muirite Group

62.01.01.01 Muirite Ba10Ca2MnTiSi10O30(OH,Cl,F)10 P 4/mmm 4/m 2/m 2/m

62.01.01.02 Cerchiaraite! Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26 I 4/mmm 4/m 2/m 2/m

Strunz Class:

09.CF.25 09 - SILICATES (Germanates)

09.C - Cyclosilicates

09.CF -[Si4O12]8- 4-membered single rings, with insular complex anions

09.CF.25 Cerchiaraite! Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26 I 4/mmm 4/m 2/m 2/m

Other Cerchiaraite Information

References:

NAME( AmMin, Vol 86) PHYS. PROP.(AmMin, Vol 86) OPTIC PROP.(AmMin, Vol 86)

See Also:

Links to other databases for Cerchiaraite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Ask about Cerchiaraite here :
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Print or Cut-and-Paste your Cerchiaraite Specimen Label here :

Cerchiaraite

Ba4(Mn,Fe,Al)4Si6(O,OH,Cl)26
Dana No: 62.01.01.02 Strunz No: 09.CF.25
Locality:

Notes: