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Brockite Mineral Data

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General Brockite Information

Help on Chemical  Formula: Chemical Formula: (Ca,Th,Ce)(PO4)•(H2O)
Help on Composition: Composition: Molecular Weight = 220.66 gm
   Calcium     10.90 %  Ca   15.25 % CaO
   Cerium       6.35 %  Ce    7.44 % Ce2O3
   Thorium     31.55 %  Th   35.90 % ThO2
   Phosphorus  14.04 %  P    32.16 % P2O5
   Hydrogen     0.91 %  H     8.16 % H2O
   Oxygen      36.25 %  O
              ______        ______ 
              100.00 %       98.91 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Ca0.6Th0.3Ce0.1(PO4)•(H2O)
Help on Environment: Environment: A rare accessory mineral in granite and granite pegmatites.
Help on IMA Status: IMA Status: Approved IMA 1962
Help on Locality: Locality: In the USA, in a prospect pit about one km east of the Bassick mine, Querida, Wet Mountains, and at the Hardwick mine and Nightingale shaft, Custer Co., Colorado. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: To honor Maurice R. Brock, U.S. Geological Survey, who supplied the first specimen.
Help on Name Pronunciation: Name Pronunciation: Brockite Say BROCKITE
Help on Synonym: Synonym: Silicosmirnovskite
  Smirnovskite
 

Brockite Image

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  Brockite

Comments: Red-brown opaque massive brockite.
Location: Anna Lee Mine, Custer County, Colorado, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Brockite Crystallography

Help on Axial Ratios: Axial Ratios: a:c = 1:0.9169
Help on Cell Dimensions: Cell Dimensions: a = 6.98, c = 6.4, Z = 3; V = 270.04 Den(Calc)= 4.07
Help on Crystal System: 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/Io): 3.03(1), 2.83(0.7), 4.37(0.7),
 

Physical Properties of Brockite

Help on Cleavage: Cleavage: None
Help on Color: Color: White, Light yellow, Dark reddish brown, Reddish brown.
Help on Density: Density: 3.7 - 4.1, Average = 3.9
Help on Diaphaneity: Diaphaneity: Translucent
Help on Fracture: Fracture: Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Help on Hardness: Hardness: 3-4 - Calcite-Fluorite
Help on Luster: Luster: Vitreous - Greasy
 

Optical Properties of Brockite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.069 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.108 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1689,KPDmeas= 0.1763,KC= 0.1893
Ncalc = 1.7 - 1.78
Help on Optical Data: Optical Data: Uniaxial (+), w=1.68, e=1.695, bire=0.0150.
 

Calculated Properties of Brockite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.60 gm/cc
note: Specific Gravity of Brockite =3.90 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0003228265
Boson Index = 0.9996771735
Help on Photoelectric: Photoelectric: PEBrockite = 753.16 barns/electron
U=PEBrockite x relectron=2,710.28 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 620,989.29 (Gamma Ray American Petroleum Institute Units)
Concentration of Brockite per GRapi unit =1,610.33 (PPB)

Brockite 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) 48.98 ± 12.25 grams of pure Brockite .
Estimated Maximum U.S. Postal Shipping Size (10 mRem/hr limit, Unshielded 100 cm box) 4898.1 ±1224.5 grams of pure Brockite .

Estimated Radioactivity from Brockite - 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 / 7.88 cm 14,133,252 3.82E-04 620,989.29 204.16
100 gm / 3.66 cm 1,413,325 3.82E-05 62,098.93 20.42
10 gm / 1.70 cm 141,333 3.82E-06 6,209.89 2.04
1 gm / 7.88 mm 14,133 3.82E-07 620.99 0.20
0.1 gm / 3.66 mm 1,413 3.82E-08 62.10 0.02
0.01 gm / 1.70 mm 141 3.82E-09 6.21 0.00
0.001 gm / 0.79 mm 14 3.82E-10 0.62 0.00

Weight of pure Brockite in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.90 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
 

Brockite Classification

Help on  Dana Class: Dana Class: 40.04.07.05 (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
Help on  Strunz Class: 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 Brockite Information

Help on References: References: NAME( AntBidBlaNic4) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
Help on See Also: See Also: Links to other databases for Brockite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - Uranium Minerals
18 - WWW-MINCRYST

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

Brockite

(Ca,Th,Ce)(PO4)•(H2O)
Dana No: 40.04.07.05 Strunz No: 08.CJ.45
Locality:

 

Notes:

 

 
   
 


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