Brittle - Uneven - Very brittle fracture producing uneven fragments.
Habit:
Cubic Crystals - Occurs as cubic shaped crystals.
Habit:
Massive - Granular - Common texture observed in granite and other igneous rock.
Habit:
Twinning Common - Crystals are usually twinned.
Hardness:
5.5 - Knife Blade
Luster:
Adamantine - Metallic
Streak:
reddish brown
Optical Properties of Loparite-(Ce)
Gladstone-Dale:
CI meas= -0.033 (Excellent) - where the CI = (1-KPDmeas/KC) CI calc= -0.029 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2756,KPDmeas= 0.2767,KC= 0.2678 Ncalc = 2.28
Optical Data:
Isotropic, n=2.26-2.38.
RL Color:
Light gray or white with a creamy tinge and brownish red internal reflections.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Loparite-(Ce) in Air
λ
R
∑ R(λ)
400 nm
18.80
420 nm
18.20
440 nm
17.80
460 nm
17.30
480 nm
17.00
500 nm
16.80
520 nm
16.60
540 nm
16.40
560 nm
16.30
580 nm
16.10
600 nm
16.10
620 nm
16.00
640 nm
15.90
660 nm
15.90
680 nm
15.90
700 nm
15.80
Calculated Relative Intensity Colors of Loparite-(Ce) in Air
Relative Intensity
0%
60%
100%
120%
180%
240%
300%
360%
420%
480%
540%
R
Calculated Properties of Loparite-(Ce)
Electron Density:
Bulk Density (Electron Density)=4.41 gm/cc note: Specific Gravity of Loparite-(Ce) =4.79 gm/cc.
Fermion Index:
Fermion Index = 0.03 Boson Index = 0.97
Photoelectric:
PELoparite-(Ce) = 146.73 barns/electron U=PELoparite-(Ce) x relectron= 646.49 barns/cc.
Radioactivity:
GRapi = 24,983.70 (Gamma Ray American Petroleum Institute Units)
Concentration of Loparite-(Ce) per GRapi unit = 40.03 (PPM)
Loparite-(Ce) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.
Estimated Radioactivity from Loparite-(Ce) - weak
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 / 7.36 cm
570,396
1.54E-05
24,983.70
8.21
100 gm / 3.42 cm
57,040
1.54E-06
2,498.37
0.82
10 gm / 1.59 cm
5,704
1.54E-07
249.84
0.08
1 gm / 7.36 mm
570
1.54E-08
24.98
0.01
0.1 gm / 3.42 mm
57
1.54E-09
2.50
0.00
0.01 gm / 1.59 mm
6
1.54E-10
0.25
0.00
0.001 gm / 0.74 mm
1
1.54E-11
0.02
0.00
Weight of pure Loparite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.79 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
Estimated Thorium Activity ( 1.27 % Th) From Sum REE Elements (25.46 % REE)
Chemical Formula: 
Small.jpg)
- weak