Atencioite Mineral Data

General Atencioite Information

Chemical Formula: Ca2Fe++[ ]Mg2Fe++2Be4(PO4)6(OH)4•6H2O Composition: Molecular Weight = 1,060.05 gm    Calcium      7.07 %  Ca    9.89 % CaO    Magnesium    5.14 %  Mg    8.52 % MgO    Manganese    0.98 %  Mn    1.27 % MnO    Beryllium    3.34 %  Be    9.27 % BeO    Aluminum     0.20 %  Al    0.38 % Al₂O₃    Iron        13.17 %  Fe   13.42 % FeO /  3.92 % Fe₂O₃    Phosphorus  17.53 %  P    40.17 % P₂O₅    Hydrogen     1.47 %  H    13.15 % H₂O    Oxygen      51.09 %  O               ______        ______                100.00 %      100.00 % = TOTAL OXIDE Empirical Formula: Ca_1.87Mg_2.24Mn²⁺_0.19Fe²⁺_1.98Fe³⁺_0.52Al_0.08Be_3.93(PO₄)₆(OH)_4.22·5.63(H₂O) Environment: Occurs in granite pegmatite. Related to roscherite. IMA Status: Approved IMA 2004 (Dana # Added) Locality: Linopolis, Divino das Laranjeiras, Minas Gerais State, Brazil Link to MinDat.org Location Data. Name Origin: Named for Dr. Daniel Atencio, professor of mineralogy at the Geoscience Institute of the University of São Paulo, Brazil. Synonym: IMA2004-041  

Atencioite Image

Images:

Atencioite Comments: Nodule of tan atenciote. Location: Pomaroli Mine, Linópolis,Minas Gerais, Brazil. Scale: Specimen size 1 cm. © Adam Larson

Atencioite Crystallography

Axial Ratios: a:b:c =0.6749:1:1.0004 Cell Dimensions: a = 6.668, b = 9.879, c = 9.883, Z = 1; alpha = 73.53°, beta = 85.6°, gamma = 86.93° V = 621.58 Den(Calc)= 2.83 Crystal System: Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1 X Ray Diffraction: By Intensity(I/I_o): 5.92(1), 2.784(0.86), 3.17(0.53),9.47(0.41), 3.31(0.34), 2.202(0.32), 2.639(0.3), 2.225(0.26),  

Physical Properties of Atencioite

Cleavage: None Color: Greenish brown. Density: 2.84 - 2.86, Average = 2.84 Diaphaneity: Transparent Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals. Habit: Concretionary - Rounded massive fine-grained materials. Habit: Spherical - Spherical, rounded aggregates. Hardness: 4.5 - Between Fluorite and Apatite Luster: Vitreous (Glassy) Streak: white  

Optical Properties of Atencioite

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= 0.219,KPDmeas= 0.2174,KC= 0.2192
Ncalc = 1.62 - 1.63 Optical Data: Biaxial (-), a=1.613, b=1.62, g=1.626, bire=0.0130, 2V(Calc)=84, 2V(Meas)=60. Dispersion dispersion not observed.  

Calculated Properties of Atencioite

Electron Density: Bulk Density (Electron Density)=2.81 gm/cc
note: Specific Gravity of Atencioite =2.83 gm/cc.
Fermion Index: Fermion Index = 0.04
Boson Index = 0.96 Photoelectric: PE_Atencioite = 5.99 barns/electron
U=PE_Atencioite x rElectron Density= 16.86 barns/cc.
Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Atencioite is Not Radioactive  

Atencioite Classification

Dana Class: 42.07.07.05 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen   (42.07)where (AB)5 (XO4)3 Zq · x(H2O)   (42.07.07)Roscherite group  

42.07.07.01 Roscherite Ca(Mn,Fe)5Be4(PO4)6(OH)4•6(H2O) C1 1

 

42.07.07.03 Zanazziite Ca2(Mg,Fe)(Mg,Fe,Al,Mn,Fe)4Be4(PO4)6(OH)4•6(H2O) C 2/c 2/m

 

42.07.07.04 Greifensteinite! Ca2Be4(Fe,Mn)5(PO4)6(OH)4•6(H2O) C 2/c 2/m

 

42.07.07.05 Atencioite! Ca2Fe[]Mg2Fe2Be4(PO4)6(OH)4•6H2O P1 1

 

42.07.07.06 Guimaraesite Ca2(Zn,Mg,Fe)5Be4(PO4)6(OH)4•6H2O C 2/c 2/m

 

42.07.07.07 Footemineite! Ca2MnMn2Mn2Be4(PO4)6(OH)4•6H2O P1 1

 

42.07.07.08 Ruifrancoite! Ca2([],Mn)2(Fe,Mn,Mg)4Be4(PO4)6(OH)4•6H2O C 2/c 2/m

Strunz Class: 08.DA.10 08 - PHOSPHATES, ARSENATES, VANADATES   08.D - Phosphates, etc   08.DA -With small (and occasionally larger) cations  

08.DA.10 Roscherite Ca(Mn,Fe)5Be4(PO4)6(OH)4•6(H2O) C1 1

 

08.DA.10 Zanazziite Ca2(Mg,Fe)(Mg,Fe,Al,Mn,Fe)4Be4(PO4)6(OH)4•6(H2O) C 2/c 2/m

 

08.DA.10 Footemineite! Ca2MnMn2Mn2Be4(PO4)6(OH)4•6H2O P1 1

 

08.DA.10 Atencioite! Ca2Fe[]Mg2Fe2Be4(PO4)6(OH)4•6H2O P1 1

 

08.DA.10 Greifensteinite! Ca2Be4(Fe,Mn)5(PO4)6(OH)4•6(H2O) C 2/c 2/m

 

08.DA.10 Ruifrancoite! Ca2([],Mn)2(Fe,Mn,Mg)4Be4(PO4)6(OH)4•6H2O C 2/c 2/m

 

08.DA.10 Guimaraesite Ca2(Zn,Mg,Fe)5Be4(PO4)6(OH)4•6H2O C 2/c 2/m

 

Other Atencioite Information

References: NAME( Doklady Chemistry, 2004, 398, pp. 191-195) PHYS. PROP.(Doklady Chemistry, 2004, 398, pp. 191-195) OPTIC PROP.(Doklady Chemistry, 2004, 398, pp. 191-195) See Also: Links to other databases for Atencioite :
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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