Crichtonite Mineral Data

Crichtonite Mineral Data

General Crichtonite Information

Chemical Formula:

(Sr,La,Ce,Y)(Ti,Fe+++,Mn)21O38

Composition:

Molecular Weight = 1,772.61 gm

Strontium 3.46 % Sr 4.09 % SrO

Lanthanum 1.57 % La 1.84 % La₂O₃

Cerium 0.79 % Ce 0.93 % Ce₂O₃

Yttrium 0.50 % Y 0.64 % Y₂O₃

Titanium 38.09 % Ti 63.54 % TiO₂

Manganese 2.17 % Mn 3.12 % Mn₂O₃

Iron 17.96 % Fe 12.56 % FeO / 11.71 % Fe₂O₃

Lead 1.17 % Pb 1.26 % PbO

Oxygen 34.30 % O

______ ______

100.00 % 99.68 % = TOTAL OXIDE

Empirical Formula:

Sr_0.7La_0.2Ce_0.1Y_0.1Pb_0.1Ti_14.1Fe²⁺_3.1Fe³⁺_2.6Mn³⁺_0.7O₃₈

Environment:

In alpine-type fissure veins.

IMA Status:

Valid Species (Pre-IMA) 1813

Locality:

St. Christopher, Bourg d'Oisans, Isere, France. Link to MinDat.org Location Data.

Name Origin:

Named for Sir Alexander A. Crichton (1763-1856), Scottish physician and mineral collector.

Synonym:

ICSD 12122

PDF 22-1121

Crichtonite Image

Images:

Crichtonite

Comments: Black crichtonite crystal in quartz.
Location: Kriegalptal, Binntal, Wallis (Valais), Switzerland. Scale: Picture size 1.5 mm.
© Thomas Witzke / Abraxas-Verlag

Crichtonite Crystallography

Axial Ratios:

a:c = 1:2.00077

Cell Dimensions:

a = 10.374, c = 20.756, Z = 3; V = 1,934.49 Den(Calc)= 4.56

Crystal System:

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

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

By Intensity(I/I_o): 2.131(1), 2.875(1), 3.39(1),

Crystal Structure:

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Grey I E , Lloyd D J , White J S , American Mineralogist , 61 (1976) p.1203-1212, The structure of crichtonite and its relationship to senaite

Physical Properties of Crichtonite

Color:

Black.

Density:

4.46

Diaphaniety:

Opaque

Habit:

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

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Metallic - Dull

Streak:

dark gray

Calculated Properties of Crichtonite

Electron Density:

r_electron=4.30 gm/cc
note: r_Crichtonite=4.56 gm/cc.

Fermion Index

Fermion Index = 0.05823
Boson Index = 0.94177

Photoelectric:

PE_Crichtonite= 47.08 barns/electron
U=PE_Crichtonite x r_electron= 202.44 barns/cc.

Radioactivity:

GRapi = 2,371.55 (Gamma Ray American Petroleum Institute Units)

**Estimated Radioactivity from Crichtonite** - mild
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 / 7.48 cm	52,812	1.43E-06	2,371.55	0.78
100 gm / 3.47 cm	5,281	1.43E-07	237.16	0.08
10 gm / 1.61 cm	528	1.43E-08	23.72	0.01
1 gm / 7.48 mm	53	1.43E-09	2.37	0.00
0.1 gm / 3.47 mm	5	1.43E-10	0.24	0.00
0.01 gm / 1.61 mm	1	1.43E-11	0.02	0.00
0.001 gm / 0.75 mm	0	1.43E-12	0.00	0.00

Weight of pure Crichtonite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.56 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 ( 0.12 % Th) From Sum REE Elements ( 2.36 % REE)

Crichtonite Classification

Dana Class:

8.5.1.3 (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.09-40 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 Crichtonite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

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

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Crichtonite

(Sr,La,Ce,Y)(Ti,Fe+++,Mn)21O38
Dana No: 8.5.1.3 Strunz No: IV/C.09-40
Locality:

Notes: