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Physical Properties of Pyrobelonite
Cleavage:
None
Color:
Dark red.
Density:
5.377
Diaphaneity:
Transparent
Fracture:
Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Hardness:
3.5 - Copper Penny
Luster:
Adamantine
Streak:
red orange
Optical Properties of Pyrobelonite
Gladstone-Dale:
CI meas= -0.274 (Poor) - where the CI = (1-KPDmeas/KC) CI calc= -0.175 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2316,KPDmeas= 0.2511,KC= 0.197 Ncalc = 2.06 - 2.15
Optical Data:
Biaxial (-), a=2.32, b=2.36, g=2.37, bire=0.0500, 2V(Calc)=52, 2V(Meas)=29. Dispersion r > v.
Pleochroism (x):
shades of brown.
Pleochroism (y):
shades of brown.
Pleochroism (z):
shades of brown.
RL Anisotrophism:
Strong.
RL Bireflectance:
Observable.
RL Color:
Gray with red and orange internal reflections.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Pyrobelonite in Air
λ
R1
R2
∑ R1(λ)
∑ R2(λ)
400 nm
17.00
19.70
420 nm
16.70
19.30
440 nm
16.50
18.90
460 nm
16.20
18.50
480 nm
16.00
18.20
500 nm
15.70
17.80
520 nm
15.50
17.40
540 nm
15.20
17.00
560 nm
15.00
16.70
580 nm
14.80
16.50
600 nm
14.70
16.30
620 nm
14.60
16.10
640 nm
14.50
16.00
660 nm
14.30
15.80
680 nm
14.20
15.70
700 nm
14.10
15.60
Calculated Relative Intensity Colors of Pyrobelonite in Air
Relative Intensity
0%
60%
100%
120%
180%
240%
300%
360%
420%
480%
540%
600%
R1
R2
Calculated Properties of Pyrobelonite
Electron Density:
Bulk Density (Electron Density)=5.06 gm/cc note: Specific Gravity of Pyrobelonite =5.83 gm/cc.
Fermion Index:
Fermion Index = 0.11 Boson Index = 0.89
Photoelectric:
PEPyrobelonite = 936.74 barns/electron U=PEPyrobelonite x rElectron Density=4,739.40 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Pyrobelonite is Not Radioactive
Pyrobelonite Classification
Dana Class:
41.05.02.03(41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen
Chemical Formula: 
