Monazite-(Nd) Mineral Data

General Monazite-(Nd) Information

Chemical Formula:

(Nd,Ce,La)(P,Si)O4

Composition:

Molecular Weight = 240.72 gm

Lanthanum 14.43 % La 16.92 % La₂O₃

Cerium 11.64 % Ce 13.64 % Ce₂O₃

Thorium 4.82 % Th 5.48 % ThO₂

Silicon 2.92 % Si 6.24 % SiO₂

Phosphorus 9.65 % P 22.11 % P₂O₅

Neodymium 29.96 % Nd 34.94 % Nd₂O₃

Oxygen 26.59 % O

______ ______

100.00 % 99.34 % = TOTAL OXIDE

Empirical Formula:

Nd_0.5La_0.25Ce_0.2Th_0.05(PO₄)_0.75(SiO₄)_0.25

Environment:

Granitic pegmatites.

IMA Status:

Approved IMA 1987

Locality:

Mars Hill, Madison County, North Carolina. Link to MinDat.org Location Data.

Name Origin:

From the Greek monazeis - "to be alone" in allusion to its isolated crystals and their rarity when first found.

Name Pronunciation:

Monazite-(Nd)

Synonym:

ICSD 79750

PDF 46-1392

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Monazite-(Nd) Crystallography

Axial Ratios:

a:b:c =0.9686:1:0.9215

Cell Dimensions:

a = 6.79, b = 7.01, c = 6.46, Z = 4; beta = 103.633° V = 298.82 Den(Calc)= 5.35

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/n

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

By Intensity(I/I_o): 3.08(1), 3.28(0.6), 2.846(0.5),

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Forms: ( 0 2 1) ( 0 1 0) ( 1 1 1) ( 1 0 1) ( 1 1 0) ( 1 0 0) ( 1 0 1)

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Crystal Structure:

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Ni Y , Hughes J M , Mariano A N , American Mineralogist , 80 (1995) p.21-26, Crystal chemistry of the monazite and xenotime structures, Nd(PO4)

Physical Properties of Monazite-(Nd)

Cleavage:

{001} Distinct, {100} Indistinct

Color:

Brown, Red, Yellow, Orange.

Density:

4.8 - 5.5, Average = 5.15

Diaphaneity:

Translucent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Habit:

Twinning Common - Crystals are usually twinned.

Hardness:

5-5.5 - Apatite-Knife Blade

Luster:

Adamantine - Resinous

Streak:

grayish white

Optical Properties of Monazite-(Nd)

Gladstone-Dale:

CI meas= -0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.032 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1502,KPDmeas= 0.1561,KC= 0.1552
Ncalc = 1.74 - 1.85

Optical Data:

Biaxial (+), a=1.77-1.8, b=1.7705-1.802, g=1.83-1.85, bire=0.0500-0.0600

Calculated Properties of Monazite-(Nd)

Electron Density:

Bulk Density (Electron Density)=4.58 gm/cc
note: Specific Gravity of Monazite-(Nd) =5.15 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_{Monazite-(Nd)}= 421.14 barns/electron
U=PE_{Monazite-(Nd)} x r_electron=1,929.92 barns/cc.

Radioactivity:

GRapi = 91,491.56 (Gamma Ray American Petroleum Institute Units)
Concentration of Monazite-(Nd) per GRapi unit = 10.93 (PPM)

Monazite-(Nd) 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) 332.45 ± 83.11 grams of pure Monazite-(Nd) .

**Estimated Radioactivity from Monazite-(Nd)** - weak
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Becquerels (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 7.18 cm	2,159,206	5.84E-05	91,491.56	30.08
100 gm / 3.33 cm	215,921	5.84E-06	9,149.16	3.01
10 gm / 1.55 cm	21,592	5.84E-07	914.92	0.30
1 gm / 7.18 mm	2,159	5.84E-08	91.49	0.03
0.1 gm / 3.33 mm	216	5.84E-09	9.15	0.00
0.01 gm / 1.55 mm	22	5.84E-10	0.91	0.00
0.001 gm / 0.72 mm	2	5.84E-11	0.09	0.00

Weight of pure Monazite-(Nd) in grams (gm) and Calculated Diameter of a Sphere with a Density of 5.15 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

Monazite-(Nd) Classification

Dana Class:

38.04.03.05 (38)Anhydrous Phosphates, etc

(38.04)A+ XO4

(38.04.03)Monazite Group (Monoclinic: P21/n)

38.04.03.01 Monazite-(Ce) (Ce,La,Nd,Th)PO4 P 2₁/n 2/m

38.04.03.02 Monazite-(La) (La,Ce,Nd)PO4 P 2₁/n 2/m

38.04.03.03 Cheralite-(Ce)? (Ce,Ca,Th)(P,Si)O4 P 2₁/n 2/m

38.04.03.04 Brabantite? CaTh(PO4)2 P 2₁ 2

38.04.03.05 Monazite-(Nd) (Nd,Ce,La)(P,Si)O4 P 2₁/n 2/m

38.04.03.06 Gasparite-(Ce) CeAsO4 P 2₁/n 2/m

38.04.03.07 Monazite-(Sm)! SmPO4 P 2₁/n 2/m

Strunz Class:

08.AD.50 08 - PHOSPHATES, ARSENATES, VANADATES

08.A - Phosphates, etc. without additional anions, without H2O

08.AD -With only large cations

08.AD.50 Brabantite? CaTh(PO4)2 P 2₁ 2

08.AD.50 Gasparite-(Ce) CeAsO4 P 2₁/n 2/m

08.AD.50 Monazite-(Ce) (Ce,La,Nd,Th)PO4 P 2₁/n 2/m

08.AD.50 Monazite-(La) (La,Ce,Nd)PO4 P 2₁/n 2/m

08.AD.50 Monazite-(Nd) (Nd,Ce,La)(P,Si)O4 P 2₁/n 2/m

08.AD.50 Rooseveltite BiAsO4 P 2/m 2/m

08.AD.50 Monazite-(Sm)! SmPO4 P 2₁/n 2/m

Other Monazite-(Nd) Information

References:

NAME( Sinkankas66) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Mason68)

See Also:

Links to other databases for Monazite-(Nd) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info
13 - Uranium Minerals

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Print or Cut-and-Paste your Monazite-(Nd) Specimen Label here :

Monazite-(Nd)

(Nd,Ce,La)(P,Si)O4
Dana No: 38.04.03.05 Strunz No: 08.AD.50
Locality:

Notes: