Benitoite Gem mine, head waters of the San Benito River, Joaquin Ridge, Diablo Range, 1 mile south of Santa Rita Peak, San Benito Co. California. Link to MinDat.org Location Data.
Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Euhedral Crystals - Occurs as well-formed crystals showing good external form.
Hardness:
5-5.5 - Apatite-Knife Blade
Luminescence:
Non-fluorescent.
Luster:
Vitreous (Glassy)
Optical Properties of Joaquinite-(Ce)
Gladstone-Dale:
CI meas= -0.022 (Excellent) - where the CI = (1-KPDmeas/KC) CI calc= 0.064 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1853,KPDmeas= 0.2024,KC= 0.198 Ncalc = 1.72 - 1.82
Bulk Density (Electron Density)=3.49 gm/cc note: Specific Gravity of Joaquinite-(Ce) =3.80 gm/cc.
Fermion Index:
Fermion Index = 0.04 Boson Index = 0.96
Photoelectric:
PEJoaquinite-(Ce) = 196.52 barns/electron U=PEJoaquinite-(Ce) x relectron= 685.10 barns/cc.
Radioactivity:
GRapi = 19,322.82 (Gamma Ray American Petroleum Institute Units)
Concentration of Joaquinite-(Ce) per GRapi unit = 51.75 (PPM)
Joaquinite-(Ce) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.
Estimated Radioactivity from Joaquinite-(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 / 7.95 cm
442,304
1.20E-05
19,322.82
6.35
100 gm / 3.69 cm
44,230
1.20E-06
1,932.28
0.64
10 gm / 1.71 cm
4,423
1.20E-07
193.23
0.06
1 gm / 7.95 mm
442
1.20E-08
19.32
0.01
0.1 gm / 3.69 mm
44
1.20E-09
1.93
0.00
0.01 gm / 1.71 mm
4
1.20E-10
0.19
0.00
0.001 gm / 0.80 mm
0
1.20E-11
0.02
0.00
Weight of pure Joaquinite-(Ce) in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.80 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 ( 0.99 % Th) From Sum REE Elements (19.75 % REE)