Tristramite Mineral Data

General Tristramite Information

Chemical Formula:

(Ca,U++++,Fe+++)(PO4,SO4)•2(H2O)

Composition:

Molecular Weight = 232.32 gm

Calcium 10.35 % Ca 14.48 % CaO

Uranium 30.74 % U 34.87 % UO₂

Iron 2.40 % Fe 3.44 % Fe₂O₃

Phosphorus 10.00 % P 22.91 % P₂O₅

Hydrogen 1.74 % H 15.51 % H₂O

Sulfur 3.45 % S 8.62 % SO₃

Oxygen 41.32 % O

______ ______

100.00 % 99.83 % = TOTAL OXIDE

Empirical Formula:

Ca_0.6U_0.3Fe³⁺_0.1(PO₄)_0.75(SO₄)_0.25•2(H₂O)

Environment:

Fractures and cavities in hydrothermal veins.

IMA Status:

Approved IMA 1983

Locality:

Wheal Trewavas, England. Link to MinDat.org Location Data.

Name Origin:

Named for Sir Tristram, a figure in the Arthurian legend.

Name Pronunciation:

Tristramite + Pronunciation

Tristramite Image

Images:

Tristramite

Comments: Reflected light, crossed polars showing a cavity with tristramite (white) infill and surrounded by intergrowth of marcasite (dark) and pitchblende (dark). (MinMag, v47:344).
Location: Wheal Trewavas Head dumps, Cornwall, UK. Scale: Scale bar = 0.1 mm.
© Mineralogical Magazine

Tristramite Crystallography

Axial Ratios:

a:c = 1:0.92897

Cell Dimensions:

a = 6.913, c = 6.422, Z = 3; V = 265.79 Den(Calc)= 4.35

Crystal System:

Hexagonal - Trapezohedral H-M Symbol (6 2 2) Space Group: P 6₂22

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

By Intensity(I/I_o): 2.83(1), 2.99(1), 2.14(0.5),

Physical Properties of Tristramite

Cleavage:

None

Color:

Green yellow, Light yellow.

Density:

3.8 - 4.2, Average = 4

Diaphaneity:

Translucent

Hardness:

3-4 - Calcite-Fluorite

Luster:

Greasy (Oily)

Optical Properties of Tristramite

Gladstone-Dale:

CI meas= 0.121 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.192 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1503,KPDmeas= 0.1635,KC= 0.186
Ncalc = 1.71 - 1.81

Optical Data:

Uniaxial (+), w=1.644, e=1.664, bire=0.0200.

Calculated Properties of Tristramite

Electron Density:

Bulk Density (Electron Density)=3.77 gm/cc
note: Specific Gravity of Tristramite =4.00 gm/cc.

Fermion Index:

Fermion Index = 0.0033222458
Boson Index = 0.9966777542

Photoelectric:

PE_Tristramite= 742.96 barns/electron
U=PE_Tristramite x r_electron=2,800.22 barns/cc.

Radioactivity:

GRapi = 2,468,740.13 (Gamma Ray American Petroleum Institute Units)
Concentration of Tristramite per GRapi unit = 405.06 (PPB)

Tristramite 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) 12.32 ± 3.08 grams of pure Tristramite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 1232.1 ±308.02 grams of pure Tristramite .

**Estimated Radioactivity from Tristramite** - very 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 / 7.82 cm	55,020,742	1.49E-03	2,468,740.13	811.64
100 gm / 3.63 cm	5,502,074	1.49E-04	246,874.01	81.16
10 gm / 1.68 cm	550,207	1.49E-05	24,687.40	8.12
1 gm / 7.82 mm	55,021	1.49E-06	2,468.74	0.81
0.1 gm / 3.63 mm	5,502	1.49E-07	246.87	0.08
0.01 gm / 1.68 mm	550	1.49E-08	24.69	0.01
0.001 gm / 0.78 mm	55	1.49E-09	2.47	0.00

Weight of pure Tristramite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.00 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

Tristramite Classification

Dana Class:

40.04.07.06 (40)Hydrated Phosphates, etc

(40.04)where A+++ XO4 � x(H2O)

(40.04.07)Rhabdophane Group

40.04.07.01 Rhabdophane-(Ce) (Ce,La)PO4•(H2O) P 6₂22 6 2 2

40.04.07.02 Rhabdophane-(La) (La,Ce)PO4•(H2O) P 6₂22 6 2 2

40.04.07.03 Rhabdophane-(Nd) (Nd,Ce,La)PO4•(H2O) P 6₂22 6 2 2

40.04.07.04 Grayite (Th,Pb,Ca)PO4•(H2O) P 6₂22 6 2 2

40.04.07.05 Brockite (Ca,Th,Ce)(PO4)•(H2O) P 6₂22 6 2 2

40.04.07.06 Tristramite (Ca,U,Fe)(PO4,SO4)•2(H2O) P 6₂22 6 2 2

Strunz Class:

08.CJ.45 08 - PHOSPHATES, ARSENATES, VANADATES

08.C - Phosphates without Additional Anions, with H2O

08.CJ -With only large cations

08.CJ.45 Brockite (Ca,Th,Ce)(PO4)•(H2O) P 6₂22 6 2 2

08.CJ.45 Grayite (Th,Pb,Ca)PO4•(H2O) P 6₂22 6 2 2

08.CJ.45 Rhabdophane-(Ce) (Ce,La)PO4•(H2O) P 6₂22 6 2 2

08.CJ.45 Rhabdophane-(La) (La,Ce)PO4•(H2O) P 6₂22 6 2 2

08.CJ.45 Rhabdophane-(Nd) (Nd,Ce,La)PO4•(H2O) P 6₂22 6 2 2

08.CJ.45 Tristramite (Ca,U,Fe)(PO4,SO4)•2(H2O) P 6₂22 6 2 2

Other Tristramite Information

References:

NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Tristramite :
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 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - Uranium Minerals

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Tristramite

(Ca,U++++,Fe+++)(PO4,SO4)•2(H2O)
Dana No: 40.04.07.06 Strunz No: 08.CJ.45
Locality:

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