Benyacarite Mineral Data

Benyacarite Mineral Data +

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General Benyacarite Information

Chemical Formula:

(H2O,K)2Ti(Mn++,Fe++)2(Fe+++,Ti)2Ti(PO4)4(O,F)2·14(H2O)

Composition:

Molecular Weight = 959.61 gm

Potassium 1.22 % K 1.47 % K₂O

Sodium 0.24 % Na 0.32 % Na₂O

Magnesium 0.25 % Mg 0.42 % MgO

Titanium 7.98 % Ti 13.32 % TiO₂

Manganese 8.59 % Mn 11.09 % MnO

Aluminum 0.28 % Al 0.53 % Al₂O₃

Iron 10.48 % Fe 2.99 % FeO / 11.65 % Fe₂O₃

Phosphorus 12.91 % P 29.58 % P₂O₅

Hydrogen 3.11 % H 27.78 % H₂O

Oxygen 53.35 % O

Fluorine 1.58 % F 1.58 % F

- % F -0.67 % -O=F₂

______ ______

100.00 % 100.08 % = TOTAL OXIDE

Empirical Formula:

(H₂O)_0.8K_0.3Na_0.1Mn²⁺_1.5Fe²⁺_0.4Mg_0.1Fe³⁺_1.4Ti_0.6Al_0.1Ti(PO₄)₄O_1.2F_0.8·14(H₂O)

Environment:

Phosphate-bearing granitic pegmatites.

IMA Status:

Approved IMA 1993

Locality:

El Criollo mine, Cerro Balnco mining district in the Sierra Grande, near Tanti, Cordoba Province, Argentina. Link to MinDat.org Location Data.

Name Origin:

For Maria Angelica R. de Benyacar (1928-), Comision Nacional de Energia Atomica, Buenos Ares, Argentina, for her contribution to mineralogical studies.

Synonym:

ICSD 67962

IMA1995-002

PDF 44-1404

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Benyacarite Crystallography

Axial Ratios:

a:b:c =0.513:1:0.608

Cell Dimensions:

a = 10.561, b = 20.585, c = 12.516, Z = 4; V = 2,720.96 Den(Calc)= 2.34

Crystal System:

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

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

By Intensity(I/I_o): 3.13(1), 6.26(1), 10.29(0.9),

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Crystal Structure:

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Demartin F , Pilati T , Gay H D , Gramaccioli C M , Zeitschrift fur Kristallographie , 208 (1993) p.57-71, The crystal structure of a mineral related to paulkerrite, Locality: granitic pegmatites in Cerro Blanco, Tanti, Cordoba, Argentina

Physical Properties of Benyacarite

Cleavage:

[010] Perfect

Color:

Yellow, Colorless, Yellowish white, Greenish yellow.

Density:

2.4

Diaphaniety:

Transparent to translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Hardness:

2.5-3 - Finger Nail-Calcite

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Benyacarite

Gladstone-Dale:

CI meas= 0.016 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.009 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2681,KPDmeas= 0.2614,KC= 0.2657

Optical Data:

Biaxial (+), a=1.612, b=1.621, g=1.649, bire=0.0370, 2V(Calc)=60, 2V(Meas)=60.

Pleochroism (x):

None.

Pleochroism (y):

None.

Pleochroism (z):

None.

Calculated Properties of Benyacarite

Electron Density:

r_electron=2.35 gm/cc
note: r_Benyacarite=2.34 gm/cc.

Fermion Index

Fermion Index = 0.01305
Boson Index = 0.98695

Photoelectric:

PE_Benyacarite= 7.27 barns/electron
U=PE_Benyacarite x r_electron= 17.08 barns/cc.

Radioactivity:

GRapi = 17.69 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Benyacarite - barely detectable

Benyacarite Classification

Dana Class:

42.11.21.4 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.21)Dana Group

42.11.21.1 Paulkerrite K(Mg,Mn)2(Fe,Al)2Ti(PO4)4(OH)3·15(H2O) P bca 2/m 2/m 2/m

42.11.21.2 Mantienneite KMg2Al2Ti(PO4)4(OH)3·15(H2O) P bca 2/m 2/m 2/m

42.11.21.3 Matveevite? KTiMn2Fe2(PO4)4(OH)3·15(H2O) Pnam ro P na2₁ Ortho

42.11.21.4 Benyacarite (H2O,K)2Ti(Mn,Fe)2(Fe,Ti)2Ti(PO4)4(O,F)2·14(H2O) P bca 2/m 2/m 2/m

Strunz Class:

VII/D.33-30 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of very big and medium size: Al, Mg and Ca, Na, K

VII/D.33 - Montgomeryite group, Mantienneite - Benyacarite series

VII/D.33-10 Mantienneite KMg2Al2Ti(PO4)4(OH)3·15(H2O) P bca 2/m 2/m 2/m

VII/D.33-20 Paulkerrite K(Mg,Mn)2(Fe,Al)2Ti(PO4)4(OH)3·15(H2O) P bca 2/m 2/m 2/m

VII/D.33-30 Benyacarite (H2O,K)2Ti(Mn,Fe)2(Fe,Ti)2Ti(PO4)4(O,F)2·14(H2O) P bca 2/m 2/m 2/m

Other Benyacarite Information

References:

NAME( MinRec) PHYS. PROP.(37th List of New Min.,Min. Mag.,1996) OPTIC PROP.(AntBidBlaNic4)

See Also:

Links to other databases for Benyacarite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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Benyacarite

(H2O,K)2Ti(Mn++,Fe++)2(Fe+++,Ti)2Ti(PO4)4(O,F)2·14(H2O)
Dana No: 42.11.21.4 Strunz No: VII/D.33-30
Locality:

Notes: