Cerite-(La) Mineral Data

General Cerite-(La) Information

Chemical Formula:

(La,Ce,Ca)9(Mg,Fe+++)(SiO4)6[SiO3(OH)](OH)3

Composition:

Molecular Weight = 1,825.93 gm

Strontium 1.68 % Sr 1.99 % SrO

Calcium 3.69 % Ca 5.16 % CaO

Lanthanum 32.41 % La 38.01 % La₂O₃

Cerium 20.49 % Ce 24.00 % Ce₂O₃

Praeseodymium 0.54 % Pr 0.63 % Pr₂O₃

Samarium 0.08 % Sm 0.10 % Sm₂O₃

Gadolinium 0.17 % Gd 0.20 % Gd₂O₃

Magnesium 0.31 % Mg 0.51 % MgO

Iron 0.98 % Fe 1.26 % FeO

Silicon 9.78 % Si 20.93 % SiO₂

Phosphorus 1.09 % P 2.49 % P₂O₅

Hydrogen 0.36 % H 3.24 % H₂O

Neodymium 1.26 % Nd 1.47 % Nd₂O₃

Oxygen 27.16 % O

______ ______

100.00 % 99.97 % = TOTAL OXIDE

Empirical Formula:

La_4.26Ce_2.67Ca_1.38Sr_0.35Nd_0.16Pr_0.07Gd_0.02Sm_0.01Fe²⁺_0.32Ca_0.3Mg_0.23(SiO₄)₃4(Si_0.84) 4(P_0.16)4(O_3.11)4(OH)(OH)_2.56

Environment:

Late-stage, low-temperature, secondary phase in a zoned aegirine-natrolite vein that cuts foyaite.

IMA Status:

Approved IMA 2002 (Dana # Added)

Locality:

Mt. Yuksporr, Khibina massif, Kola Peninsula, Russia. Link to MinDat.org Location Data.

Name Origin:

Named as the La dominant analog of cerite-(Ce).

Synonym:

IMA2001-042

Cerite-(La) Image

Images:

Cerite-(La)

Comments: Orange aggregates of cerite-(La) in matrix, (CanMin, 40:1179).
Location: Mt. Yuksporr, Khibina massif, Kola Peninsula, Russia. Scale: Specimen size 3.5 cm.
© Canadian Mineralogist

Images:

Cerite-(La)

Comments: SEM photomicrograph of a rhombohedral crystal of cerite-(La).
Location: Mt. Yuksporr, Khibina massif, Kola Peninsula, Russia. Scale: Crystal size 2 mm.
© Canadian Mineralogist

Cerite-(La) Crystallography

Axial Ratios:

a:c = 1:3.56469

Cell Dimensions:

a = 10.7493, c = 38.318, Z = 6; V = 3,834.37 Den(Calc)= 4.74

Crystal System:

Trigonal - Ditrigonal Pyramidal H-M Symbol (3m) Space Group: R 3c

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

By Intensity(I/I_o): 2.958(1)(0.2.10), 3.47(0.4)(122), 3.31(0.38)(214),2.833(0.37)(128), 1.949(0.34)(238,1.3.13), 2.689(0.34)(220), 3.53(0.26)(1.0.10), 3.1(0.25)(300), 2.79(0.24)(306),

Physical Properties of Cerite-(La)

Cleavage:

None

Color:

Light yellow, Pinkish brown.

Density:

4.7

Diaphaneity:

Translucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Equant Grains - Granular material with equel dimensions in x, y, and z.

Habit:

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

Hardness:

5 - Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Cerite-(La)

Gladstone-Dale:

CI meas= -0.018 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.01 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1719,KPDmeas= 0.1734,KC= 0.1703
Ncalc = 1.8 - 1.81

Optical Data:

Uniaxial (+), w=1.81, e=1.82, bire=0.0100.

Calculated Properties of Cerite-(La)

Electron Density:

Bulk Density (Electron Density)=4.28 gm/cc
note: Specific Gravity of Cerite-(La) =4.74 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Cerite-(La)= 274.35 barns/electron
U=PE_Cerite-(La) x r_electron=1,174.39 barns/cc.

Radioactivity:

GRapi = 52,941.91 (Gamma Ray American Petroleum Institute Units)
Concentration of Cerite-(La) per GRapi unit = 18.89 (PPM)

Cerite-(La) 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) 574.53 ±143.63 grams of pure Cerite-(La) .

**Estimated Radioactivity from Cerite-(La)** - 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 / 7.39 cm	1,231,087	3.33E-05	52,941.91	17.41
100 gm / 3.43 cm	123,109	3.33E-06	5,294.19	1.74
10 gm / 1.59 cm	12,311	3.33E-07	529.42	0.17
1 gm / 7.39 mm	1,231	3.33E-08	52.94	0.02
0.1 gm / 3.43 mm	123	3.33E-09	5.29	0.00
0.01 gm / 1.59 mm	12	3.33E-10	0.53	0.00
0.001 gm / 0.74 mm	1	3.33E-11	0.05	0.00

Weight of pure Cerite-(La) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.74 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
Estimated Thorium Activity ( 2.75 % Th) From Sum REE Elements (54.95 % REE)

Cerite-(La) Classification

Dana Class:

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

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

(52.04.06)Cerite Group

52.04.06.01 Cerite-(Ce) Ce9Fe(SiO4)6[(SiO3)(OH)](OH)3 R 3c 3m

52.04.06.02 Cerite-(La)! (La,Ce,Ca)9(Mg,Fe)(SiO4)6[SiO3(OH)](OH)3 R 3c 3m

52.04.06.03 Aluminocerite-(Ce)! (Ce,REE,Ca)9(Al,Fe)(SiO4)3[SiO3(OH)]4(OH)3 R 3c 3m

Strunz Class:

09.AG.20 09 - SILICATES (Germanates)

09.A - Nesosilicates

09.AG -Nesosilicates with additional anions; cations in > [6] � [6] coordination

09.AG.20 Cerite-(Ce) Ce9Fe(SiO4)6[(SiO3)(OH)](OH)3 R 3c 3m

09.AG.20 Cerite-(La)! (La,Ce,Ca)9(Mg,Fe)(SiO4)6[SiO3(OH)](OH)3 R 3c 3m

09.AG.20 Aluminocerite-(Ce)! (Ce,REE,Ca)9(Al,Fe)(SiO4)3[SiO3(OH)]4(OH)3 R 3c 3m

Other Cerite-(La) Information

References:

NAME( AmMin, 88:1175) PHYS. PROP.(AmMin, 88:1175) OPTIC PROP.(AmMin, 88:1175)

See Also:

Links to other databases for Cerite-(La) :
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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Print or Cut-and-Paste your Cerite-(La) Specimen Label here :

Cerite-(La)

(La,Ce,Ca)9(Mg,Fe+++)(SiO4)6[SiO3(OH)](OH)3
Dana No: 52.04.06.02 Strunz No: 09.AG.20
Locality:

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