Grayite Mineral Data

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General Grayite Information

Chemical Formula:

(Th,Pb,Ca)PO4•(H2O)

Composition:

Molecular Weight = 318.38 gm

Calcium 1.26 % Ca 1.76 % CaO

Thorium 43.73 % Th 49.76 % ThO₂

Phosphorus 9.73 % P 22.29 % P₂O₅

Hydrogen 0.63 % H 5.66 % H₂O

Lead 19.52 % Pb 21.03 % PbO

Oxygen 25.13 % O

______ ______

100.00 % 100.50 % = TOTAL OXIDE

Empirical Formula:

Th_0.6Pb_0.3Ca_0.1(PO₄)•(H₂O)

Environment:

Lithium pegmatites.

IMA Status:

Valid Species (Pre-IMA) 1957

Locality:

Gooddays mine, Mtoko, and the Mahaka claim, Wedza, Zimbabwe. Link to MinDat.org Location Data.

Name Origin:

Named for Anton Gray, mining engineer, advisor to U. K. Atomic Energy Authority.

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Grayite Crystallography

Axial Ratios:

a:c = 1:0.91936

Cell Dimensions:

a = 6.957, c = 6.396, Z = 2; V = 268.09 Den(Calc)= 3.94

Crystal System:

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

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

By Intensity(I/I_o): 3.04(1), 2.14(0.8), 2.82(0.8),

Physical Properties of Grayite

Cleavage:

None

Color:

Light yellow, Reddish brown.

Density:

3.7 - 4.3, Average = 4

Diaphaneity:

Translucent

Fracture:

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

Habit:

Aggregates - Made of numerous individual crystals or clusters.

Habit:

Cryptocrystalline - Occurs as crystals too small to distinguish with the naked eye.

Hardness:

3-4 - Calcite-Fluorite

Luster:

Resinous

Optical Properties of Grayite

Gladstone-Dale:

CI meas= 0.035 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.02 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1713,KPDmeas= 0.1688,KC= 0.1748
Ncalc = 1.65 - 1.75

Optical Data:

Uniaxial (?), a=1.66, b=1.69, bire=0.0300.

Calculated Properties of Grayite

Electron Density:

Bulk Density (Electron Density)=3.41 gm/cc
note: Specific Gravity of Grayite =3.94 gm/cc.

Fermion Index:

Fermion Index = 0.04
Boson Index = 0.96

Photoelectric:

PE_Grayite=1,411.61 barns/electron
U=PE_Grayite x r_electron=4,807.49 barns/cc.

Radioactivity:

GRapi = 806,368.42 (Gamma Ray American Petroleum Institute Units)
Concentration of Grayite per GRapi unit =1,240.13 (PPB)

Grayite 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) 37.72 ± 9.43 grams of pure Grayite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 3772.1 ±943.01 grams of pure Grayite .

**Estimated Radioactivity from Grayite** - 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 / 7.86 cm	19,590,543	5.29E-04	806,368.42	265.11
100 gm / 3.65 cm	1,959,054	5.29E-05	80,636.84	26.51
10 gm / 1.69 cm	195,905	5.29E-06	8,063.68	2.65
1 gm / 7.86 mm	19,591	5.29E-07	806.37	0.27
0.1 gm / 3.65 mm	1,959	5.29E-08	80.64	0.03
0.01 gm / 1.69 mm	196	5.29E-09	8.06	0.00
0.001 gm / 0.79 mm	20	5.29E-10	0.81	0.00

Weight of pure Grayite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.94 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

Grayite Classification

Dana Class:

40.04.07.04 (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 Grayite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Grayite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - MinMax(Deutsch)
11 - MinMax(English)
12 - Mineralienatlas (Deutsch)
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - Uranium Minerals

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Grayite

(Th,Pb,Ca)PO4•(H2O)
Dana No: 40.04.07.04 Strunz No: 08.CJ.45
Locality:

Notes: