Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Anhedral Grains - Granular minerals without the expression of crystal shapes
Habit:
Microscopic Crystals - Crystals visible only with microscopes.
Hardness:
5-5.5 - Apatite-Knife Blade
Luster:
Adamantine
Streak:
pale greenish brown
Optical Properties of Rengeite
Optical Data:
Biaxial (+)
NCalc= 1.99 - from Gladstone-Dale relationship (KC = 0.2419) where Ncalc=Dcalc*KC+1
Calculated Properties of Rengeite
Electron Density:
Bulk Density (Electron Density)=3.82 gm/cc note: Specific Gravity of Rengeite =4.08 gm/cc.
Fermion Index:
Fermion Index = 0.05 Boson Index = 0.95
Photoelectric:
PERengeite = 50.65 barns/electron U=PERengeite x relectron= 193.39 barns/cc.
Radioactivity:
GRapi = 678.56 (Gamma Ray American Petroleum Institute Units)
Concentration of Rengeite per GRapi unit =1,473.72 (PPM)
Estimated Radioactivity from Rengeite - 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 / 7.76 cm
15,226
4.12E-07
678.56
0.22
100 gm / 3.60 cm
1,523
4.12E-08
67.86
0.02
10 gm / 1.67 cm
152
4.12E-09
6.79
0.00
1 gm / 7.76 mm
15
4.12E-10
0.68
0.00
0.1 gm / 3.60 mm
2
4.12E-11
0.07
0.00
0.01 gm / 1.67 mm
0
4.12E-12
0.01
0.00
0.001 gm / 0.78 mm
0
4.12E-13
0.00
0.00
Weight of pure Rengeite in grams (gm) and Calculated Diameter of a Sphere with a Density of 4.08 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 ( 0.03 % Th) From Sum REE Elements ( 0.68 % REE)
Rengeite Classification
Dana Class:
56.02.08.05(56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O
(56.02)with cations in [4] and/or >[4] coordination
Chemical Formula: 
- mild