Monazite-(Ce) Mineral Data

[Content and History] [Recent Issues] [Back Issues] [Subscriptions] [Contacts]
See Also: [Diamond Crystals] [Excalibur Minerals] [Hudson Institute] [Minerals on CDROM]
Mineral News was founded some twenty years ago and has developed a following of
avid mineral collectors seeking timely information about new finds and other items
of interest to the collector community. Articles are solicited from collector and scientific authors.

General Monazite-(Ce) Information

Chemical Formula:

(Ce,La,Nd,Th)PO4

Composition:

Molecular Weight = 240.21 gm

Lanthanum 14.46 % La 16.95 % La₂O₃

Cerium 29.17 % Ce 34.16 % Ce₂O₃

Thorium 4.83 % Th 5.50 % ThO₂

Phosphorus 12.89 % P 29.55 % P₂O₅

Neodymium 12.01 % Nd 14.01 % Nd₂O₃

Oxygen 26.64 % O

______ ______

100.00 % 100.17 % = TOTAL OXIDE

Empirical Formula:

Ce_0.5La_0.25Nd_0.2Th_0.05(PO₄)

Environment:

Granitic pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1829

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-(Ce)

Synonym:

Cheralite-(Ce)

ICSD 79746

PDF 32-199

Monazite-(Ce) Image

Images:

Monazite-(Ce)

Comments: Orange crystals of monazite-(Ce) on lepidolite.
Location: Conselheiro Pena, Minas Gerais, Brazil. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Monazite-(Ce) 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)= 5.34

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): 2.862(1), 3.078(0.8), 1.963(0.5),

Forms:

Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize
Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu
Help on Above

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

Warning: this large pop-up is very compute intensive and may not work well with some computers.

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

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

View Additional jPOWD Structure files for Monazite-(Ce)
[1]

Physical Properties of Monazite-(Ce)

Cleavage:

{001} Distinct, {100} Indistinct

Color:

Brown, Colorless, Greenish, Gray white, Yellow.

Density:

4.8 - 5.5, Average = 5.15

Diaphaneity:

Subtransparent to subtranslucent

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

Luminescence:

Non-fluorescent.

Luster:

Adamantine - Resinous

Streak:

grayish white

Optical Properties of Monazite-(Ce)

Gladstone-Dale:

CI meas= -0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.032 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1517,KPDmeas= 0.1572,KC= 0.1567
Ncalc = 1.75 - 1.86

Optical Data:

Biaxial (+), a=1.785-1.8, b=1.787-1.801, g=1.837-1.849, bire=0.0490-0.0520, 2V(Calc)=18-24, 2V(Meas)=6-25. Dispersion r > v or r < v.

Pleochroism (x):

colorless or light yellow.

Pleochroism (y):

colorless or dark yellow.

Calculated Properties of Monazite-(Ce)

Electron Density:

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

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_{Monazite-(Ce)}= 407.22 barns/electron
U=PE_{Monazite-(Ce)} x r_electron=1,864.04 barns/cc.

Radioactivity:

GRapi = 91,584.34 (Gamma Ray American Petroleum Institute Units)
Concentration of Monazite-(Ce) per GRapi unit = 10.92 (PPM)

Monazite-(Ce) 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) 332.12 ± 83.03 grams of pure Monazite-(Ce) .

**Estimated Radioactivity from Monazite-(Ce)** - weak
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 / 7.18 cm	2,163,839	5.85E-05	91,584.34	30.11
100 gm / 3.33 cm	216,384	5.85E-06	9,158.43	3.01
10 gm / 1.55 cm	21,638	5.85E-07	915.84	0.30
1 gm / 7.18 mm	2,164	5.85E-08	91.58	0.03
0.1 gm / 3.33 mm	216	5.85E-09	9.16	0.00
0.01 gm / 1.55 mm	22	5.85E-10	0.92	0.00
0.001 gm / 0.72 mm	2	5.85E-11	0.09	0.00

Weight of pure Monazite-(Ce) 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-(Ce) Classification

Dana Class:

38.04.03.01 (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-(Ce) Information

See Also:

Links to other databases for Monazite-(Ce) :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - MinMax(Deutsch)
11 - MinMax(English)
12 - Mineralienatlas (Deutsch)
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - Uranium Minerals
16 - WWW-MINCRYST

Search for Monazite-(Ce) using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Monazite-(Ce) :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Desert Winds Gems and Minerals

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

Wrights Rock Shop

Translate Monazite-(Ce) Mineral Data :

Ask about Monazite-(Ce) here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Monazite-(Ce)

(Ce,La,Nd,Th)PO4
Dana No: 38.04.03.01 Strunz No: 08.AD.50
Locality:

Notes: