Baumstarkite Mineral Data
General Baumstarkite Information
Chemical Formula:
Ag3(Sb,As)2SbS6
Composition:
Molecular Weight = 869.54 gm
Silver 37.22 % Ag
Antimony 38.50 % Sb
Arsenic 2.15 % As
Sulfur 22.13 % S
______
100.00 %
Empirical Formula:
Ag3 Sb2.75 As0.25 S6
Environment:
Found coating miargyrite. Polymorphic relationship with miargyrite and cuboargyrite
IMA Status:
Approved IMA 2002 (Dana # Added)
Locality:
San Genaro mine, Huancavelica Department, Peru. Link to MinDat.org Location Data.
Name Origin:
Named for Manfred Baumstark(1954-), German mineralogist who first recognized the mineral.
Synonym:
IMA1999-049
Baumstarkite Image
Images:
Baumstarkite
Comments: Fragments of baumstarkite with zoning of darker lamellae with higher As content. (AmMin 87:755).
Location: San Genaro mine, Huancavelica Department, Peru..
Scale: See Image.
© American Mineralogist
Baumstarkite Crystallography
Axial Ratios:
a:b:c =0.9331:1:1.0591
Cell Dimensions:
a = 7.766, b = 8.322, c = 8.814, Z = 2; alpha = 100.62°, beta = 104.03°, gamma = 90.22° V = 543.17 Den(Calc)= 5.32
Crystal System:
Triclinic - Pinacoidal H-M Symbol ( 1 ) Space Group: P1
X Ray Diffraction:
By Intensity(I/Io ): 2.798(1)(003), 2.841(0.88)(22 1,221 ), 3.158(0.8)(201),
3.425(0.8)(021), 1.3994(0.6)(006), 3.224(0.6)(202 ), 1.971(0.5)(224 ), 2.013(0.5)(222), 3.258(0.3)(02<
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Physical Properties of Baumstarkite
Cleavage:
{001} Perfect, {100} Good
Color:
Iron black, Grayish black.
Density:
5.33
Diaphaneity:
Opaque
Fracture:
Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).
Habit:
Inclusions - Generally found as inclusions in other minerals.
Habit:
Tabular - Form dimensions are thin in one direction.
Hardness:
2.5 - Finger Nail
Luster:
Metallic
Streak:
grayish black
Optical Properties of Baumstarkite
Optical Data:
NCalc= 1.36 - from Gladstone-Dale relationship (KC = 0.0672) where Ncalc =Dcalc *KC +1 NCalc= 1.36 - from Gladstone-Dale relationship (KC = 0.0672) where Ncalc =Dmeas *KC +1
RL Anisotrophism:
Strong to weak.
RL Bireflectance:
Weak to moderate.
RL Color:
Gray to white.
RL Pleochroism:
None.
Reflectivity
Standardized Intensity (100%) Reflection Spectra of Baumstarkite in Air
λ
R1
R 2
∑ R1 (λ)
∑ R2 (λ)
400 nm
33.15
40.95
420 nm
32.70
40.75
440 nm
32.15
40.20
460 nm
31.60
39.65
480 nm
31.10
39.50
500 nm
30.40
38.80
520 nm
29.95
38.10
540 nm
29.35
37.40
560 nm
28.60
36.80
580 nm
28.10
36.45
600 nm
27.60
35.70
620 nm
27.05
34.65
640 nm
26.45
33.60
660 nm
25.90
32.70
680 nm
25.45
32.40
700 nm
25.15
31.25
Standardized Intensity (100%) Reflection Spectra of Baumstarkite in Oil
λ
R1
R 2
∑ R1 (λ)
∑ R2 (λ)
400 nm
19.20
25.95
420 nm
18.40
25.25
440 nm
17.60
24.30
460 nm
17.00
23.80
480 nm
16.40
23.30
500 nm
15.80
22.60
520 nm
15.25
21.80
540 nm
14.70
21.30
560 nm
14.10
20.75
580 nm
13.65
20.50
600 nm
13.20
19.80
620 nm
12.80
18.85
640 nm
12.30
17.90
660 nm
11.95
17.25
680 nm
11.75
16.60
700 nm
11.70
16.30
Calculated Relative Intensity Colors of Baumstarkite in Air
Relative Intensity
0%
40%
80%
100%
120%
160%
200%
240%
280%
320%
R1
R2
Calculated Relative Intensity Colors of Baumstarkite in Oil
Relative Intensity
0%
70%
100%
140%
210%
280%
350%
420%
490%
560%
630%
660%
R1
R2
Calculated Properties of Baumstarkite
Electron Density:
Bulk Density (Electron Density)=4.72 gm/cc note: Specific Gravity of Baumstarkite =5.32 gm/cc.
Fermion Index:
Fermion Index = 0.0016594569 Boson Index = 0.9983405431
Photoelectric:
PEBaumstarkite = 226.23 barns/electronU=PEBaumstarkite x r Electron Density=1,067.14 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Baumstarkite is Not Radioactive
Baumstarkite Classification
Dana Class:
03.07.04.02 (03) Sulfides - Sulfosalts
(03.07) where z/y = 2 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals
(03.07.04) Dana Group
03.07.04.01 Aramayoite Ag3Sb2(Sb,Bi)S6 P1 1
03.07.04.02 Baumstarkite ! Ag3(Sb,As)2SbS6 P1 1
Strunz Class:
02.HA.25 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf
02.H - Sulfosalts of SnS Archetype
02.HA -With Cu, Ag, Fe (without Pb)
02.HA.25 Aramayoite Ag3Sb2(Sb,Bi)S6 P1 1
02.HA.25 Baumstarkite ! Ag3(Sb,As)2SbS6 P1 1
Other Baumstarkite Information
References:
NAME( AmMin, Vol 87, p 735) PHYS. PROP.(AmMin, Vol 87, p 735) OPTIC PROP.(AmMin, Vol 87, p 735)
See Also:
Links to other databases for Baumstarkite :
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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Baumstarkite
Ag3(Sb,As)2SbS6
Dana No: 03.07.04.02 Strunz No: 02.HA.25
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