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 % K2 O
Sodium 0.24 % Na 0.32 % Na2 O
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 % Al2 O3
Iron 10.48 % Fe 2.99 % FeO / 11.65 % Fe2 O3
Phosphorus 12.91 % P 29.58 % P2 O5
Hydrogen 3.11 % H 27.78 % H2 O
Oxygen 53.35 % O
Fluorine 1.58 % F 1.58 % F
- %
F -0.67 % -O=F2
______ ______
100.00 % 100.08 % = TOTAL OXIDE
Empirical Formula:
(H2 O)0.8 K0.3 Na0.1 Mn2+ 1.5 Fe2+ 0.4 Mg0.1 Fe3+ 1.4 Ti0.6 Al0.1 Ti(PO4 )4 O1.2 F0.8 �14(H2 O)
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
X Ray Diffraction:
By Intensity(I/Io ): 3.13(1), 6.26(1), 10.29(0.9),
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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:
PEBenyacarite = 7.27 barns/electronU=PEBenyacarite 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 � 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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Print or Cut-and-Paste your Benyacarite Specimen Label here :
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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