Grayite Mineral Data

Grayite Mineral Data

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.

Search for Grayite Images

Images:

Image not yet available on Webmineral.com

Try searching images.google.com or Mindat Picture Gallary for mineral pictures. Caution: The images retrieved may not be appropriate.

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

Diaphaniety:

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

Optical Data:

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

Calculated Properties of Grayite

Electron Density:

r_electron=3.41 gm/cc
note: r_Grayite=3.94 gm/cc.

Fermion Index

Fermion Index = 0.04328
Boson Index = 0.95672

Photoelectric:

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

Radioactivity:

GRapi = 806,367.94 (Gamma Ray American Petroleum Institute Units)

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	19,590,538	5.29E-04	806,367.94	265.11
100 gm / 3.65 cm	1,959,054	5.29E-05	80,636.79	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:

40.4.7.4 (40)Hydrated Phosphates, etc

(40.4)where A+++ XO4 · x(H2O)

(40.4.7)Dana Group

40.4.7.1 Rhabdophane-(Ce) (Ce,La)PO4·(H2O) P 6₂22 6 2 2

40.4.7.2 Rhabdophane-(La) (La,Ce)PO4·(H2O) P 6₂22 6 2 2

40.4.7.3 Rhabdophane-(Nd) (Nd,Ce,La)PO4·(H2O) P 6₂22 6 2 2

40.4.7.4 Grayite (Th,Pb,Ca)PO4·(H2O) P 6₂22 6 2 2

40.4.7.5 Brockite (Ca,Th,Ce)(PO4)·(H2O) P 6₂22 6 2 2

40.4.7.6 Tristramite (Ca,U,Fe)(PO4,SO4)·2(H2O) P 6₂22 6 2 2

Strunz Class:

VII/C.29-60 VII - Phosphates, Arsenates and Vanadates

VII/C - Water-bearing phosphates without unfamiliar anions, cations of medium and big size: Fe, Mn, Zn, Mg and Ca, (NH4)1+

VII/C.29 - Rhabdophane group

VII/C.29-10 Rhabdophane-(Ce) (Ce,La)PO4·(H2O) P 6₂22 6 2 2

VII/C.29-20 Rhabdophane-(La) (La,Ce)PO4·(H2O) P 6₂22 6 2 2

VII/C.29-30 Rhabdophane-(Nd) (Nd,Ce,La)PO4·(H2O) P 6₂22 6 2 2

VII/C.29-40 Brockite (Ca,Th,Ce)(PO4)·(H2O) P 6₂22 6 2 2

VII/C.29-50 Tristramite (Ca,U,Fe)(PO4,SO4)·2(H2O) P 6₂22 6 2 2

VII/C.29-60 Grayite (Th,Pb,Ca)PO4·(H2O) P 6₂22 6 2 2

VII/C.29-70 Ningyoite (U,Ca,Ce)2(PO4)2·1-2(H2O) P 222 2 2 2

Other Grayite Information

References:

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

Search for Grayite using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Grayite :

AA Mineral Specimens

B & L Fine Minerals

Crystal Vaults

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

MineralsWeb Fine Minerals

Rockshop.cz

T G Fine Minerals

Wrights Rock Shop

Translate Grayite Mineral Data :

Ask about Grayite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Grayite

(Th,Pb,Ca)PO4·(H2O)
Dana No: 40.4.7.4 Strunz No: VII/C.29-60
Locality:

Notes: