Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Habit:
Platy - Sheet forms (e.g. micas).
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:
1 - Talc
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Ilmajokite
Gladstone-Dale:
CI meas= -0.006 (Superior) - where the CI = (1-KPDmeas/KC) CI calc= -0.011 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.263,KPDmeas= 0.2618,KC= 0.2601 Ncalc = 1.57
Bulk Density (Electron Density)=2.21 gm/cc note: Specific Gravity of Ilmajokite =2.20 gm/cc.
Fermion Index:
Fermion Index = 0.02 Boson Index = 0.98
Photoelectric:
PEIlmajokite = 45.12 barns/electron U=PEIlmajokite x relectron= 99.69 barns/cc.
Radioactivity:
GRapi = 5,492.68 (Gamma Ray American Petroleum Institute Units)
Concentration of Ilmajokite per GRapi unit = 182.06 (PPM)
Ilmajokite is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.
Estimated Radioactivity from Ilmajokite - mild
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 / 9.54 cm
114,865
3.10E-06
5,492.68
1.81
100 gm / 4.43 cm
11,487
3.10E-07
549.27
0.18
10 gm / 2.06 cm
1,149
3.10E-08
54.93
0.02
1 gm / 9.54 mm
115
3.10E-09
5.49
0.00
0.1 gm / 4.43 mm
11
3.10E-10
0.55
0.00
0.01 gm / 2.06 mm
1
3.10E-11
0.05
0.00
0.001 gm / 0.95 mm
0
3.10E-12
0.01
0.00
Weight of pure Ilmajokite in grams (gm) and Calculated Diameter of a Sphere with a Density of 2.20 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 ( 0.26 % Th) From Sum REE Elements ( 5.13 % REE)
Chemical Formula: 
- mild