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)_4.22ï¿½5.63(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 Sï¿½o Paulo, Brazil.

Synonym:

IMA2004-041

Atencioite Image

Images:

Atencioite

Comments: Nodule of tan atenciote.
Location: Pomaroli Mine, LinÃ³polis,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 - Pinacoidal H-M Symbol ( 1) Space Group: P1

$Help on X Ray Diffraction:$ 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 ï¿½ 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

Search for Atencioite using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Atencioite :

Ask about Atencioite 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 Atencioite Specimen Label here :

Atencioite

Ca2Fe++[ ]Mg2Fe++2Be4(PO4)6(OH)4•6H2O
Dana No: 42.07.07.05 Strunz No: 08.DA.10
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.