A secondary mineral, as an alteration of stibnite, in antimony deposits
IMA Status:
Valid Species (Pre-IMA) 1843
Locality:
Braunsdorf, near Freiberg, Saxony, Germany. Link to MinDat.org Location Data.
Name Origin:
Name from kermes, a name given from the Persian qurmizq, "crimson" in the older chemistry to red amorphous antimony trisulphide, often mixed with antimony trioxide.
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Bonazzi P , Menchetti S , Sabelli C , Neues Jahrbuch fur Mineralogie, Monatshefte , 1987 (1987) p.557-567, Structure refinement of kermesite: symmetry, twinning, and comparison with stibnite, Locality: Braunsdorf, Czechoslovakia
Physical Properties of Kermesite
Cleavage:
{100} Perfect
Color:
Violet red, Cherry red, Red.
Density:
4.5 - 4.6, Average = 4.55
Diaphaneity:
Translucent to Opaque
Fracture:
Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Fibrous - Crystals made up of fibers.
Habit:
Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Hardness:
1.5-2 - Talc-Gypsum
Luminescence:
Non-fluorescent.
Luster:
Adamantine
Magnetism:
Nonmagnetic
Streak:
brownish red
Optical Properties of Kermesite
Optical Data:
Biaxial (+), a=2.72, b=2.74, g=2.74, bire=0.0200
Pleochroism (x):
cherry red.
Pleochroism (y):
cherry red.
Pleochroism (z):
cherry red.
RL Anisotrophism:
Very strong to extreme.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Kermesite in Air
λ
R1
R2
∑ R1(λ)
∑ R2(λ)
400 nm
31.10
37.50
420 nm
30.00
36.40
440 nm
29.00
35.20
460 nm
28.00
34.00
480 nm
27.20
33.00
500 nm
26.40
32.20
520 nm
25.70
31.30
540 nm
25.20
30.60
560 nm
24.80
30.00
580 nm
24.40
29.40
600 nm
24.00
29.00
620 nm
23.80
28.60
640 nm
23.50
28.20
660 nm
23.40
28.00
680 nm
23.20
27.80
700 nm
23.10
27.70
Calculated Relative Intensity Colors of Kermesite in Air
Relative Intensity
0%
40%
80%
100%
120%
160%
200%
240%
280%
320%
360%
R1
R2
Calculated Properties of Kermesite
Electron Density:
Bulk Density (Electron Density)=4.26 gm/cc note: Specific Gravity of Kermesite =4.85 gm/cc.
Fermion Index:
Fermion Index = 0.0015099577 Boson Index = 0.9984900423
Photoelectric:
PEKermesite = 253.30 barns/electron U=PEKermesite x rElectron Density=1,078.08 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Kermesite is Not Radioactive
Kermesite Classification
Dana Class:
02.13.01.01(02)Sulfides - Including Selenides and Tellurides