Cronusite Mineral Data
General Cronusite Information
Chemical Formula:
Ca0.2(H2O)2CrS2
Composition:
Molecular Weight = 161.98 gm
Calcium 4.95 % Ca
Chromium 32.10 % Cr
Hydrogen 2.61 % H
Sulfur 39.59 % S
Oxygen 20.74 % O
______
100.00 %
Empirical Formula:
Ca0.2 (H2 O)2.1 CrS2
Environment:
Derived from the weathering of caswellsilverite and disseminated in enstatite. Close to sch�llhornite.
IMA Status:
Approved IMA 2002 (Dana # Added)
Locality:
Norton County enstatite achondrite meteorite, Kansas, USA. Link to MinDat.org Location Data.
Name Origin:
Name derived from the Greek Titan "Cronos" and alludes to the combined meteor-terrestrial origin where cronusite is derived from terretrial weathering of meteoric minerals.
Synonym:
IMA1999-018
Cronusite Image
Images:
Cronusite
Comments: Light gray grain of cronusite. Polished section (from microprobe analysis) in reflected light.
Location: Enstatite meteorite, Norton Co., Kansas, USA.
Scale: Picture size 0.18 mm.
© Thomas Witzke / Abraxas-Verlag
Cronusite Crystallography
Axial Ratios:
a:c = 1:10.00901
Cell Dimensions:
a = 3.326, c = 33.29, Z = 3; V = 318.93 Den(Calc)= 2.53
Crystal System:
Trigonal Space Group: Rm, R 3m or R 32
X Ray Diffraction:
By Intensity(I/Io ): 11.1(1)(003), 2.719(0.5)(104), 2.18(0.49)(1.1.10), 2.464(0.4)(107), 3.7(0.4)(009), 5.56(0.1)(006),
Physical Properties of Cronusite
Cleavage:
{001} Perfect
Color:
Coal black.
Density:
2.51
Diaphaneity:
Opaque
Fracture:
Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).
Habit:
Granular - Generally occurs as anhedral to subhedral crystals in matrix.
Habit:
Inclusions - Generally found as inclusions in other minerals.
Hardness:
1.5 - Between Talc and Gypsum
Luster:
Sub Metallic
Streak:
black
Optical Properties of Cronusite
RL Anisotrophism:
Strong.
RL Bireflectance:
Strong.
RL Color:
Gray with no internal reflections.
RL Pleochroism:
In gray polarization colors.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Cronusite in Air
λ
R1
R 2
∑ R1 (λ)
∑ R2 (λ)
460 nm
14.40
15.80
540 nm
15.70
17.60
580 nm
16.20
18.20
640 nm
16.60
18.60
Calculated Relative Intensity Colors of Cronusite in Air
Relative Intensity
0%
70%
100%
140%
210%
280%
350%
420%
490%
560%
610%
R1
R2
Calculated Properties of Cronusite
Electron Density:
Bulk Density (Electron Density)=2.53 gm/cc note: Specific Gravity of Cronusite =2.53 gm/cc.
Fermion Index:
Fermion Index = 0.03 Boson Index = 0.97
Photoelectric:
PECronusite = 9.72 barns/electronU=PECronusite x r Electron Density= 24.59 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Cronusite is Not Radioactive
Cronusite Classification
Dana Class:
02.09.17.03 (02) Sulfides - Including Selenides and Tellurides
(02.09) where Am Bn Xp, with (m+n):p=1:1
(02.09.17) Caswellsilverite Group
02.09.17.01 Caswellsilverite NaCrS2 R 3 m 3 2/m
02.09.17.02 Schollhornite Na0.3CrS2•(H2O) R 3m ? 3m
02.09.17.03 Cronusite ! Ca0.2(H2O)2CrS2 Rm, R 3m or R 32 Trig
Strunz Class:
02.FB.05 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
02.F - Sulfides of Arsenic, Alkalies; Sulfides with Halide, Oxide, Hydroxide, H2O
02.FB -With Alkalies (without Cl, etc.)
02.FB.05 Caswellsilverite NaCrS2 R 3 m 3 2/m
02.FB.05 Schollhornite Na0.3CrS2•(H2O) R 3m ? 3m
02.FB.05 Cronusite ! Ca0.2(H2O)2CrS2 Rm, R 3m or R 32 Trig
Other Cronusite Information
References:
NAME( AmMin, Vol 87, p 1510) PHYS. PROP.(AmMin, Vol 87, p 1510) OPTIC PROP.(AmMin, Vol 87, p 1510)
See Also:
Links to other databases for Cronusite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - Mineralienatlas (Deutsch)
10 - Online Mineral Museum
11 - QUT Mineral Atlas
12 - Ruff.Info
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Cronusite
Ca0.2(H2O)2CrS2
Dana No: 02.09.17.03 Strunz No: 02.FB.05
Locality:
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