Britholite-(Ce) Mineral Data

Britholite-(Ce) Mineral Data +

General Britholite-(Ce) Information

Chemical Formula:

(Ce,Ca,Th,La,Nd)5(SiO4,PO4)3(OH,F)

Composition:

Molecular Weight = 762.67 gm

Calcium 14.71 % Ca 20.59 % CaO

Lanthanum 7.29 % La 8.54 % La₂O₃

Cerium 16.53 % Ce 19.37 % Ce₂O₃

Thorium 18.25 % Th 20.77 % ThO₂

Silicon 9.94 % Si 21.27 % SiO₂

Phosphorus 2.03 % P 4.65 % P₂O₅

Hydrogen 0.11 % H 0.94 % H₂O

Neodymium 3.78 % Nd 4.41 % Nd₂O₃

Oxygen 26.85 % O

Fluorine 0.50 % F 0.50 % F

- % F -0.21 % -O=F₂

______ ______

100.00 % 104.44 % = TOTAL OXIDE

Empirical Formula:

Ca_2.8Ce_0.9Th_0.6La_0.4Nd_0.2Si_2.7P_0.5O₁₂(OH)_0.8F_0.2

Environment:

In nepheline syenites, pegmatites and contact deposits related to them.

IMA Status:

Valid Species (Pre-IMA) 1901

Locality:

Julianehaab, South Greenland. Link to MinDat.org Location Data.

Name Origin:

From the Greek for weight, in allusion to its density and the content of Ce.

Synonym:

Beckelite

ICSD 33858

Lessingite

Lessingite-(Ce)

PDF 31-892

Pravdite

Britholite-(Ce) Image

Images:

Britholite-(Ce)

Comments: Dark gray, parallel aggregates of britholite-(Ce) crystals in matix..
Location: Rusty Gold Mine, Jamestown District, Boulder Co., Colorado, USA. Scale: See Image.
© Paul M. Schumacher

Britholite-(Ce) Crystallography

Axial Ratios:

a:c = 1:0.73001

Cell Dimensions:

a = 9.63, c = 7.03, Z = 2; V = 564.60 Den(Calc)= 4.49

Crystal System:

Hexagonal - DipyramidalH-M Symbol (6/m) Space Group: P 6₃/m

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

By Intensity(I/I_o): 2.836(1), 3.48(0.8), 2.809(0.8),1.858(0.5), 3.211(0.4), 3.927(0.4), 4.116(0.4),

Crystal Structure:

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Noe D C , Hughes J M , Mariano A N , Drexler J W , Kato A , Zeitschrift fur Kristallographie , 206 (1993) p.233-246, The crystal structure of monoclinic britholite-(Ce) and britholite-(Y), Note: unannealed sample, Locality: the Kipawa syenite gneiss complex

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

Physical Properties of Britholite-(Ce)

Cleavage:

None

Color:

Brown, Greenish brown, Yellow, Resin brown, Black.

Density:

4.2 - 4.7, Average = 4.45

Diaphaniety:

Nearly opaque

Fracture:

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

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Habit:

Pseudo Hexagonal - Crystals show a hexagonal outline.

Hardness:

5.5 - Knife Blade

Luster:

Adamantine - Resinous

Optical Properties of Britholite-(Ce)

Dichroism (e):

colorless.

Dichroism (w):

brown.

Gladstone-Dale:

CI meas= 0.018 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.026 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1759,KPDmeas= 0.1775,KC= 0.1807

Optical Data:

Uniaxial (+/-), a=1.77, b=1.81, bire=0.0400.

Calculated Properties of Britholite-(Ce)

Electron Density:

r_electron=4.05 gm/cc
note: r_{Britholite-(Ce)}=4.45 gm/cc.

Fermion Index

Fermion Index = 0.01278
Boson Index = 0.98722

Photoelectric:

PE_{Britholite-(Ce)}= 564.09 barns/electron
U=PE_{Britholite-(Ce)} x r_electron=2,286.14 barns/cc.

Radioactivity:

GRapi = 354,673.93 (Gamma Ray American Petroleum Institute Units)

Britholite-(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) 85.76 ± 21.44 grams of pure Britholite-(Ce) .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 8576.0 ±2144.0 grams of pure Britholite-(Ce) .

**Estimated Radioactivity from Britholite-(Ce)** - 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 / 7.54 cm	8,178,079	2.21E-04	354,673.93	116.61
100 gm / 3.50 cm	817,808	2.21E-05	35,467.39	11.66
10 gm / 1.63 cm	81,781	2.21E-06	3,546.74	1.17
1 gm / 7.54 mm	8,178	2.21E-07	354.67	0.12
0.1 gm / 3.50 mm	818	2.21E-08	35.47	0.01
0.01 gm / 1.63 mm	82	2.21E-09	3.55	0.00
0.001 gm / 0.75 mm	8	2.21E-10	0.35	0.00

Weight of pure Britholite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.45 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

Britholite-(Ce) Classification

Dana Class:

52.4.9.1 (52)Nesosilicate Insular SiO4 Groups and O, OH, F, and H2O

(52.4)with cations in [6] and/or > [6] coordination

(52.4.9)Silicate apatites

52.4.9.0 Ellestadite* Ca5(SiO4,PO4,SO4)3(F,OH,Cl) P 6₃/m 6/m

52.4.9.1 Britholite-(Ce) (Ce,Ca,Th,La,Nd)5(SiO4,PO4)3(OH,F) P 6₃/m 6/m

52.4.9.2 Britholite-(Y) (Y,Ca)5(SiO4,PO4)3(OH,F) P 6₃/m 6/m

52.4.9.3 Fluorellestadite Ca5(SiO4,PO4,SO4)3(F,OH,Cl) P 6₃/m 6/m

52.4.9.4 Hydroxylellestadite Ca5(SiO4,SO4)3(OH,Cl,F) P 6₃/m 6/m

52.4.9.5 Chlorellestadite Ca5(SiO4,PO4,SO4)3(Cl,OH,F) P 6₃/m 6/m

52.4.9.6 Mattheddleite Pb20(SiO4)7(SO4)4Cl4 P 6₃/m 6/m

52.4.9.7 Karnasurtite-(Ce) (Ce,La,Th)(Ti,Nb)(Al,Fe)(Si,P)2O7(OH)4·3(H2O)(?) Unk. Hex

52.4.9.8 Fluorbritholite-(Ce) (Ca,Ce,La,Na)5(SiO4,PO4)3(OH,F) P 6₃/m 6/m

Strunz Class:

VIII/B.27-60 VIII - Silicates

VIII/B - Nesosubsilicates, with anions unfamiliar to tetraheders, with groups [SO4]2-, [CrO4]2- and [PO4]3-

VIII/B.27 - Fluorellestadite - Lessingite-(Ce) series

VIII/B.27-10 Fluorellestadite Ca5(SiO4,PO4,SO4)3(F,OH,Cl) P 6₃/m 6/m

VIII/B.27-20 Chlorellestadite Ca5(SiO4,PO4,SO4)3(Cl,OH,F) P 6₃/m 6/m

VIII/B.27-30 Hydroxylellestadite Ca5(SiO4,SO4)3(OH,Cl,F) P 6₃/m 6/m

VIII/B.27-40 Mattheddleite Pb20(SiO4)7(SO4)4Cl4 P 6₃/m 6/m

VIII/B.27-50 Britholite-(Y) (Y,Ca)5(SiO4,PO4)3(OH,F) P 6₃/m 6/m

VIII/B.27-60 Britholite-(Ce) (Ce,Ca,Th,La,Nd)5(SiO4,PO4)3(OH,F) P 6₃/m 6/m

VIII/B.27-62 Fluorbritholite-(Ce) (Ca,Ce,La,Na)5(SiO4,PO4)3(OH,F) P 6₃/m 6/m

Other Britholite-(Ce) Information

References:

NAME( Ford32) PHYS. PROP.(Bull.Miner.,Vol.107-111,1984-1988) OPTIC PROP.(AntBidBlaNic2)

See Also:

Links to other databases for Britholite-(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 - Uranium Minerals 15 - WWW-MINCRYST 16 -École des Mines de Paris

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Britholite-(Ce)

(Ce,Ca,Th,La,Nd)5(SiO4,PO4)3(OH,F)
Dana No: 52.4.9.1 Strunz No: VIII/B.27-60
Locality:

Notes: