Benyacarite Mineral Data

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_0.8ï¿½14(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.

Name Pronunciation:

Benyacarite + Pronunciation

Synonym:

ICSD 67962

IMA1995-002

PDF 44-1404

Benyacarite Image

Images:

Benyacarite

Comments: Clear, transparent, pseudo-cubic benyacarite crystals on matrix.
Location: Folgosinho Quarry, Folgosinho, Gouveia, Guarda District, Portugal. Scale: Specimen Size 4 x 3 cm.
© Sergio Varvello / Mineral Service

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 - Dipyramidal H-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),

Forms:

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Forms: ( 0 1 0) ( 1 1 1) ( 0 0 1)

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Physical Properties of Benyacarite

Cleavage:

{010} Perfect

Color:

Yellow, Colorless, Yellowish white, Greenish yellow.

Density:

2.4

Diaphaneity:

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= 0.037 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2681,KPDmeas= 0.2614,KC= 0.2713
Ncalc = 1.63 - 1.65

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:

Bulk Density (Electron Density)=2.35 gm/cc
note: Specific Gravity of Benyacarite =2.34 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

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)
Concentration of Benyacarite per GRapi unit = 5.65 (%)

Estimated Radioactivity from Benyacarite - barely detectable

Benyacarite Classification

Dana Class:

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

(42.11)where (AB)4 (XO4)3 Zq ï¿½ x(H2O)

(42.11.21)Paulkerrite Group

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

42.11.21.02 Mantienneite KMg2Al2Ti(PO4)4(OH)3•15(H2O) P bca 2/m 2/m 2/m

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

42.11.21.04 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:

08.DH.35 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DH -With large and medium-sized cations, (OH, etc.):RO4 < 1:1

08.DH.35 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

08.DH.35 Matveevite? KTiMn2Fe2(PO4)4(OH)3•15(H2O) Pnam ro P na2₁ Ortho

08.DH.35 Mantienneite KMg2Al2Ti(PO4)4(OH)3•15(H2O) P bca 2/m 2/m 2/m

08.DH.35 Paulkerrite K(Mg,Mn)2(Fe,Al)2Ti(PO4)4(OH)3•15(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 - 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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Benyacarite

(H2O,K)2Ti(Mn++,Fe++)2(Fe+++,Ti)2Ti(PO4)4(O,F)2•14(H2O)
Dana No: 42.11.21.04 Strunz No: 08.DH.35
Locality:

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