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Physical Properties of Tetrahedrite
Cleavage:
None
Color:
Iron gray, Black, Steel gray.
Density:
4.6 - 5.2, Average = 4.9
Diaphaneity:
Opaque
Fracture:
Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Habit:
Massive - Granular - Common texture observed in granite and other igneous rock.
Habit:
Massive - Uniformly indistinguishable crystals forming large masses.
Hardness:
3.5-4 - Copper Penny-Fluorite
Luminescence:
Non-fluorescent.
Luster:
Metallic
Magnetism:
Nonmagnetic
Streak:
black
Optical Properties of Tetrahedrite
Optical Data:
Isotropic, n=2.72.
RL Color:
Gray inclining to olive-brown.
RL Pleochroism:
None.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Tetrahedrite in Air
λ
R
∑ R(λ)
400 nm
30.30
420 nm
30.90
440 nm
31.50
460 nm
31.80
480 nm
31.80
500 nm
32.00
520 nm
32.40
540 nm
32.80
560 nm
33.00
580 nm
33.00
600 nm
32.50
620 nm
31.60
640 nm
31.00
660 nm
30.80
680 nm
30.60
700 nm
30.40
Calculated Relative Intensity Colors of Tetrahedrite in Air
Relative Intensity
0%
30%
60%
90%
100%
120%
150%
180%
210%
240%
270%
280%
R
Calculated Properties of Tetrahedrite
Electron Density:
Bulk Density (Electron Density)=4.52 gm/cc note: Specific Gravity of Tetrahedrite =4.95 gm/cc.
Fermion Index:
Fermion Index = 0.0040639271 Boson Index = 0.9959360729
Photoelectric:
PETetrahedrite = 116.02 barns/electron U=PETetrahedrite x rElectron Density= 524.91 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Tetrahedrite is Not Radioactive
Chemical Formula: 
