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.

Name Pronunciation:

Davidite-(La)

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:

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drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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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

Diaphaneity:

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
Ncalc = 2.52 - 2.64

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:

Bulk Density (Electron Density)=4.13 gm/cc
note: Specific Gravity of Davidite-(La) =4.42 gm/cc.

Fermion Index:

Fermion Index = 0.05
Boson Index = 0.95

Photoelectric:

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

Radioactivity:

GRapi = 261,511.25 (Gamma Ray American Petroleum Institute Units)
Concentration of Davidite-(La) per GRapi unit = 3.82 (PPM)

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 Becquerels (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	5,874,890	1.59E-04	261,511.25	85.98
100 gm / 3.51 cm	587,489	1.59E-05	26,151.12	8.60
10 gm / 1.63 cm	58,749	1.59E-06	2,615.11	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:

08.05.01.05 (08)Multiple Oxides with Nb, Ta, and Ti

(08.05)Dana Type

(08.05.01)Crichtonite group (ABC18 T2 O38)

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

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

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

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

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

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

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

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

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

08.05.01.10 Cleusonite! Pb(U,U)(Ti,Fe,Fe)20(O,OH)38 R 3 3

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

Strunz Class:

04.CC.40 04 - OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodate

04.C - Metal:Oxygen = 2:3, 3:5, and Similar

04.CC -With large and medium-sized cations

04.CC.40 Crichtonite (Sr,La,Ce,Y)(Ti,Fe,Mn)21O38 R 3 3

04.CC.40 Dessauite! (Sr,Pb)(Y,U)(Ti,Fe)20O38 P 3 3

04.CC.40 Davidite-(Ce) (Ce,La)(Y,U)(Ti,Fe)20O38 R 3 3

04.CC.40 Davidite-(La) (La,Ce,Ca)(Y,U)(Ti,Fe)20O38 R 3 3

04.CC.40 Mathiasite (K,Ca,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

04.CC.40 Lindsleyite (Ba,Sr)(Ti,Cr,Fe,Mg)21O38 R 3 3

04.CC.40 Landauite NaMnZn2(Ti,Fe)6Ti12O38 R 3 3

04.CC.40 Loveringite (Ca,Ce)(Ti,Fe,Cr,Mg)21O38 R 3 3

04.CC.40 Senaite Pb(Ti,Fe,Mn)21O38 R 3 3

04.CC.40 Cleusonite! Pb(U,U)(Ti,Fe,Fe)20(O,OH)38 R 3 3

04.CC.40 Gramaccioliite-(Y)! (Pb,Sr)(Y,Mn)Fe2(Ti,Fe)18O38 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 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
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 Davidite-(La) Specimen Label here :

Davidite-(La)

(La,Ce,Ca)(Y,U)(Ti,Fe+++)20O38
Dana No: 08.05.01.05 Strunz No: 04.CC.40
Locality:

Notes: