Menezesite Mineral Data

General Menezesite Information

Chemical Formula:

Ba2MgZr4(BaNb12O42)•12H2O

Composition:

Molecular Weight = 2,778.48 gm

Potassium 0.75 % K 0.90 % K₂O

Barium 10.82 % Ba 12.09 % BaO

Sodium 0.05 % Na 0.07 % Na₂O

Calcium 0.45 % Ca 0.63 % CaO

Lanthanum 0.10 % La 0.12 % La₂O₃

Cerium 0.86 % Ce 1.00 % Ce₂O₃

Thorium 4.59 % Th 5.23 % ThO₂

Magnesium 0.82 % Mg 1.36 % MgO

Zirconium 9.03 % Zr 12.20 % ZrO₂

Uranium 0.17 % U 0.19 % UO₂

Tantalum 2.34 % Ta 2.86 % Ta₂O₅

Titanium 5.60 % Ti 9.34 % TiO₂

Manganese 0.45 % Mn 0.59 % MnO

Niobium 30.86 % Nb 44.15 % Nb₂O₅

Aluminum 0.03 % Al 0.06 % Al₂O₃

Iron 0.46 % Fe 0.59 % FeO

Silicon 0.12 % Si 0.26 % SiO₂

Hydrogen 0.87 % H 7.78 % H₂O

Neodymium 0.52 % Nd 0.61 % Nd₂O₃

Oxygen 31.09 % O

______ ______

100.00 % 100.02 % = TOTAL OXIDE

Empirical Formula:

Ba_1.47K_0.53Ca_0.31Ce_0.17Nd_0.1Na_0.06La_0.02Mg_0.94Mn²⁺_0.23Fe²⁺_0.23Al_0.03Zr_2.75Ti_0.96 Th_0.29Ba_0.72Th_0.26U_0.02Nb_9.23Ti_2.29ï¿½12(H₂O)

Environment:

Occurs in the contact zone between dolomite carbonatite and "jacupirangite" (=a pyroxenite). First natural heteropolyniobate.

IMA Status:

Approved IMA 2005 (Dana # Added)

Locality:

Jacupiranga mine, Cajati County, Sï¿½o Paulo, Brazil. Link to MinDat.org Location Data.

Name Origin:

Named for Luiz Alberto Dias Menezes Filho (born 1950), mining engineer, mineral collector, and merchant

Synonym:

IMA2005-023

Menezesite Image

Images:

Menezesite

Comments: Orange rhombododecahedral crystals of menezesite to 0.75mm on matrix.
Location: Jacupiranga mine, Cajati county, Sao Paulo, Brazil. Scale: Picture size 1 cm.
© Tom Loomis / Dakota Matrix

Images:

Menezesite

Comments: Brownish-red rhombododecahedral crystals of menezesite over calcite (with tiny black tochilinite inclusions). AmMin v93:82.
Location: Jacupiranga mine, in Cajati county, SÃ£o Paulo state, Brazil. Scale: Crystal size 0.5 mm.
© American Mineralogist

Menezesite Crystallography

Cell Dimensions:

a = 13.017, Z = 2; V = 2,205.63 Den(Calc)= 4.18

Crystal System:

Isometric - Diploidal H-M Symbol (2/m 3) Space Group: Im3

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

By Intensity(I/I_o): 9.183(1), 1.0741(0.21), 3.256(0.16),2.655(0.13), 3.07(0.13), 4.592(0.12), 2.923(0.11), 4.136(0.11),

Physical Properties of Menezesite

Cleavage:

None

Color:

Reddish borwn.

Diaphaneity:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Rhombohedral Crystals - Occurs as well-formed crystals showing rhobohedral crystals.

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Menezesite

Gladstone-Dale:

CI calc= 0.052 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2344,KC= 0.2473
Ncalc = 2.03

Optical Data:

Isotropic, n=1.93-2.03.

Calculated Properties of Menezesite

Electron Density:

Bulk Density (Electron Density)=3.84 gm/cc
note: Specific Gravity of Menezesite =4.18 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Menezesite= 252.41 barns/electron
U=PE_Menezesite x r_electron= 968.46 barns/cc.

Radioactivity:

GRapi = 103,359.74 (Gamma Ray American Petroleum Institute Units)
Concentration of Menezesite per GRapi unit = 9.67 (PPM)

Menezesite is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 10 cm box) 294.28 ± 73.57 grams of pure Menezesite .

**Estimated Radioactivity from Menezesite** - strong
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Bequerols (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 7.70 cm	2,364,668	6.39E-05	103,359.74	33.98
100 gm / 3.57 cm	236,467	6.39E-06	10,335.97	3.40
10 gm / 1.66 cm	23,647	6.39E-07	1,033.60	0.34
1 gm / 7.70 mm	2,365	6.39E-08	103.36	0.03
0.1 gm / 3.57 mm	236	6.39E-09	10.34	0.00
0.01 gm / 1.66 mm	24	6.39E-10	1.03	0.00
0.001 gm / 0.77 mm	2	6.39E-11	0.10	0.00

Weight of pure Menezesite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.18 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem

Menezesite Classification

Dana Class:

49.02.05.01 (49)Basic and Hydrated Molybdates and Tungstates

(49.02)(Hydrated)

(49.02.05)Dana Group

49.02.05.01 Menezesite! Ba2MgZr4(BaNb12O42)•12H2O Im3 2/m 3

Strunz Class:

04.FN.05 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.F - Hydroxides (without V or U)

04.FN -

04.FN.05 Menezesite! Ba2MgZr4(BaNb12O42)•12H2O Im3 2/m 3

Other Menezesite Information

References:

NAME( AmMin, v93:81) PHYS. PROP.(AmMin, v93:81) OPTIC PROP.(AmMin, v93:81)

See Also:

Links to other databases for Menezesite :
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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Menezesite

Ba2MgZr4(BaNb12O42)•12H2O
Dana No: 49.02.05.01 Strunz No: 04.FN.05
Locality:

Notes:

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