Dessauite Mineral Data

General Dessauite Information

Chemical Formula:

(Sr,Pb)(Y,U)(Ti,Fe+++)20O38

Composition:

Molecular Weight = 1,856.57 gm

Strontium 3.54 % Sr 4.19 % SrO

Yttrium 3.35 % Y 4.26 % Y₂O₃

Uranium 3.85 % U 4.36 % UO₂

Titanium 38.68 % Ti 64.54 % TiO₂

Iron 15.04 % Fe 21.50 % Fe₂O₃

Lead 2.79 % Pb 3.01 % PbO

Oxygen 32.75 % O

______ ______

100.00 % 101.85 % = TOTAL OXIDE

Empirical Formula:

Sr_0.75Pb_0.25Y_0.7U_0.3Ti₁₅Fe³⁺₅O₃₈

Environment:

In calcite veins within dolomite. A member of the Crichtonite group.

IMA Status:

Approved IMA 1997 (Dana # Added)

Locality:

The Buca della Vena mine, Apuan Alps, near the town of Stazzema, northern Tuscany, Italy. Link to MinDat.org Location Data.

Name Origin:

For Gabor Dessau (1907-1983), professor of ore mineralogy at the University of Pisa, Italy.

Name Pronunciation:

Dessauite + Pronunciation

Synonym:

ICSD 77505

IMA1994-057

Romanite

Dessauite Image

Images:

Dessauite

Comments: SEM photograph of tabular {001} dessauite crystals on calcite. (AmMin v82:807).
Location: Buca della Vena mine, Tuscany, Italy. Scale: Scale bar: 0 .1mm.
© American Mineralogist

Dessauite Crystallography

Axial Ratios:

a:c = 1:2.01454

Cell Dimensions:

a = 10.385, c = 20.921, Z = 3; V = 1,954.01 Den(Calc)= 4.73

Crystal System:

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

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Forms: ( 1 0 0) ( 0 0 1)

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Physical Properties of Dessauite

Cleavage:

None

Color:

Black.

Density:

4.68

Diaphaneity:

Opaque

Fracture:

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

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

6.5-7 - Pyrite-Quartz

Luster:

Metallic

Streak:

black

Optical Properties of Dessauite

Optical Data:

NCalc= 2.62 - from Gladstone-Dale relationship (KC = 0.343) where Ncalc=Dcalc*KC+1
NCalc= 2.61 - from Gladstone-Dale relationship (KC = 0.343) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Weak.

RL Bireflectance:

Low.

RL Color:

Ash gray with pale blue tones.

RL Pleochroism:

Very weak.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Dessauite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	17.30	17.70
546 nm	16.60	17.10
589 nm	16.10	16.60
650 nm	16.00	16.50

**Standardized Intensity (100%) Reflection Spectra of Dessauite in Oil**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
470 nm	5.60	6.00
546 nm	5.00	5.50
589 nm	4.80	5.30
650 nm	4.60	5.10

**Calculated Relative Intensity Colors of Dessauite in Air**
Relative Intensity	0%	60%	100%	120%	180%	240%	300%	360%	420%	480%	540%	550%
R₁
R₂

**Calculated Relative Intensity Colors of Dessauite in Oil**
Relative Intensity	0%	100%	200%	300%	400%	500%	600%	700%	800%	900%	1000%
R₁
R₂

Calculated Properties of Dessauite

Electron Density:

Bulk Density (Electron Density)=4.42 gm/cc
note: Specific Gravity of Dessauite =4.73 gm/cc.

Fermion Index:

Fermion Index = 0.06
Boson Index = 0.94

Photoelectric:

PE_Dessauite= 158.61 barns/electron
U=PE_Dessauite x r_electron= 701.41 barns/cc.

Radioactivity:

GRapi = 306,522.05 (Gamma Ray American Petroleum Institute Units)
Concentration of Dessauite per GRapi unit = 3.26 (PPM)

Dessauite 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) 99.23 ± 24.81 grams of pure Dessauite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 9923.2 ±2480.8 grams of pure Dessauite .

**Estimated Radioactivity from Dessauite** - 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 / 7.39 cm	6,884,821	1.86E-04	306,522.05	100.77
100 gm / 3.43 cm	688,482	1.86E-05	30,652.21	10.08
10 gm / 1.59 cm	68,848	1.86E-06	3,065.22	1.01
1 gm / 7.39 mm	6,885	1.86E-07	306.52	0.10
0.1 gm / 3.43 mm	688	1.86E-08	30.65	0.01
0.01 gm / 1.59 mm	69	1.86E-09	3.07	0.00
0.001 gm / 0.74 mm	7	1.86E-10	0.31	0.00

Weight of pure Dessauite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.73 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

Dessauite Classification

Dana Class:

08.05.01.09 (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 Dessauite Information

References:

NAME( MinRec) PHYS. PROP.(Am.Min.,Vol.82,p807-811,1997) OPTIC PROP.(MinRec, v 29, p 235)

See Also:

Links to other databases for Dessauite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (UofA)
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info
12 - Uranium Minerals
13 - WWW-MINCRYST

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Print or Cut-and-Paste your Dessauite Specimen Label here :

Dessauite

(Sr,Pb)(Y,U)(Ti,Fe+++)20O38
Dana No: 08.05.01.09 Strunz No: 04.CC.40
Locality:

Notes: