Davidite-(La) Mineral Data

Davidite-(La) Mineral Data +

General Davidite-(La) Information

Chemical Formula:

(La,Ce,Ca)(Y,U)(Ti,Fe+++)20O38

Composition:

Molecular Weight = 1,860.86 gm

Calcium 0.22 % Ca 0.30 % CaO

Lanthanum 5.23 % La 6.13 % La₂O₃

Cerium 1.51 % Ce 1.76 % Ce₂O₃

Yttrium 3.58 % Y 4.55 % Y₂O₃

Uranium 3.20 % U 3.63 % UO₂

Titanium 38.59 % Ti 64.39 % TiO₂

Iron 15.01 % Fe 21.45 % Fe₂O₃

Oxygen 32.67 % O

______ ______

100.00 % 102.21 % = TOTAL OXIDE

Empirical Formula:

La_0.7Ce_0.2Ca_0.1Y_0.75U_0.25Ti₁₅Fe³⁺₅O₃₈

Environment:

Uranium-rich pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1906

Locality:

Radium Hill mine, Olary Province, SA, Australia. Link to MinDat.org Location Data.

Name Origin:

Named for Tenatt William Edgeworth David (1858-1934), Australian geologist.

Synonym:

ICSD 100554

PDF 42-576

Davidite-(La) Image

Images:

Davidite-(La)

Comments: Prismatic crystals of davidite in carbonatite.
Location: Thackering, South West Australia, Australia. Scale: Crystal size 2 cm.
© John Veevaert

Davidite-(La) Crystallography

Axial Ratios:

a:c = 1:2.01522

Cell Dimensions:

a = 10.376, c = 20.91, Z = 3; V = 1,949.60 Den(Calc)= 4.75

Crystal System:

Trigonal - RhombohedralH-M Symbol ( 3) Space Group: R 3

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

By Intensity(I/I_o): 2.895(1), 3.42(0.72), 2.85(0.6),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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H - Help Screen
I - Data Info
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Gatehouse B M , Grey I E , Kelly P R , American Mineralogist , 64 (1979) p.1010-1017, The crystal structure of davidite

Physical Properties of Davidite-(La)

Cleavage:

None

Color:

Black, Grayish black, Brownish black, Dark brown, Reddish.

Density:

4.42

Diaphaniety:

Opaque

Fracture:

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

Habit:

Anhedral Grains - Granular minerals without the expression of crystal shapes

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Habit:

Metamict - Mineral originally crystalline, now amorphous due to radiation damage.

Hardness:

6 - Orthoclase

Luster:

Vitreous - Metallic

Streak:

brownish black

Optical Properties of Davidite-(La)

Gladstone-Dale:

CI meas= 0.146 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.205 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2737,KPDmeas= 0.2941,KC= 0.3442

Optical Data:

Isotropic, n=2.3.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Davidite-(La) in Air**
λ	R	∑ R(λ)
400 nm	19.40
420 nm	19.00
440 nm	18.60
460 nm	18.10
480 nm	17.80
500 nm	17.50
520 nm	17.30
540 nm	17.20
560 nm	17.00
580 nm	17.00
600 nm	16.90
620 nm	16.80
640 nm	16.80
660 nm	16.80
680 nm	16.70
700 nm	16.60

**Calculated Relative Intensity Colors of Davidite-(La) in Air**
Relative Intensity	0%	60%	100%	120%	180%	240%	300%	360%	420%	480%	520%
R

Calculated Properties of Davidite-(La)

Electron Density:

r_electron=4.13 gm/cc
note: r_{Davidite-(La)}=4.42 gm/cc.

Fermion Index

Fermion Index = 0.05352
Boson Index = 0.94648

Photoelectric:

PE_{Davidite-(La)}= 124.84 barns/electron
U=PE_{Davidite-(La)} x r_electron= 515.80 barns/cc.

Radioactivity:

GRapi = 261,510.45 (Gamma Ray American Petroleum Institute Units)

Davidite-(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) 116.31 ± 29.08 grams of pure Davidite-(La) .

**Estimated Radioactivity from Davidite-(La)** - 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 / 7.56 cm	5,874,875	1.59E-04	261,510.45	85.98
100 gm / 3.51 cm	587,488	1.59E-05	26,151.05	8.60
10 gm / 1.63 cm	58,749	1.59E-06	2,615.10	0.86
1 gm / 7.56 mm	5,875	1.59E-07	261.51	0.09
0.1 gm / 3.51 mm	587	1.59E-08	26.15	0.01
0.01 gm / 1.63 mm	59	1.59E-09	2.62	0.00
0.001 gm / 0.76 mm	6	1.59E-10	0.26	0.00

Weight of pure Davidite-(La) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.42 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 ( 0.34 % Th) From Sum REE Elements ( 6.73 % REE)

Davidite-(La) Classification

Dana Class:

8.5.1.5 (8)Multiple Oxides with Nb, Ta, and Ti

(8.5)Dana Type

(8.5.1)Crichtonite group (ABC18 T2 O38)

8.5.1.1 Landauite NaMnZn2(Ti,Fe)6Ti12O38 R 3 3

8.5.1.2 Loveringite (Ca,Ce)(Ti,Fe,Cr,Mg)21O38 R 3 3

8.5.1.3 Crichtonite (Sr,La,Ce,Y)(Ti,Fe,Mn)21O38 R 3 3

8.5.1.4 Senaite Pb(Ti,Fe,Mn)21O38 R 3 3

8.5.1.5 Davidite-(La) (La,Ce,Ca)(Y,U)(Ti,Fe)20O38 R 3 3

8.5.1.6 Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe)20O38 R 3 3

8.5.1.7 Mathiasite (K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

8.5.1.8 Lindsleyite (Ba,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

8.5.1.9 Dessauite! (Sr,Pb)(Y,U)(Ti,Fe)20O38 P 3 3

8.5.1.10 Cleusonite! Pb(U,U)(Ti,Fe2,Fe3)20(O,OH)38 R 3 3

8.5.1.11 Gramaccioliite-(Y)! (Pb,Sr)(Y,Mn)Fe2(Ti,Fe)18O38 R 3 3

Strunz Class:

IV/C.09-60 IV - Oxides

IV/C - Oxides with metal : oxygen = 2:3 (M2O3 and related compounds)

IV/C.09 - Crichtonite group

IV/C.09-10 Landauite NaMnZn2(Ti,Fe)6Ti12O38 R 3 3

IV/C.09-20 Mathiasite (K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

IV/C.09-30 Loveringite (Ca,Ce)(Ti,Fe,Cr,Mg)21O38 R 3 3

IV/C.09-40 Crichtonite (Sr,La,Ce,Y)(Ti,Fe,Mn)21O38 R 3 3

IV/C.09-45 Dessauite! (Sr,Pb)(Y,U)(Ti,Fe)20O38 P 3 3

IV/C.09-50 Lindsleyite (Ba,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

IV/C.09-60 Davidite-(La) (La,Ce,Ca)(Y,U)(Ti,Fe)20O38 R 3 3

IV/C.09-62 Gramaccioliite-(Y)! (Pb,Sr)(Y,Mn)Fe2(Ti,Fe)18O38 R 3 3

IV/C.09-70 Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe)20O38 R 3 3

IV/C.09-80 Senaite Pb(Ti,Fe,Mn)21O38 R 3 3

Other Davidite-(La) Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic3)

See Also:

Links to other databases for Davidite-(La) :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Crocoite.com Mineral Locations 4 - EUROmin Project 5 -Google Images 6 -Google Scholar 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - Uranium Minerals 13 -École des Mines de Paris

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Davidite-(La)

(La,Ce,Ca)(Y,U)(Ti,Fe+++)20O38
Dana No: 8.5.1.5 Strunz No: IV/C.09-60
Locality:

Notes: