Orpiment Mineral Data + Say ORPIMENT


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General Orpiment Information
Help on Chemical Formula: Chemical Formula: As2S3
Help on Composition: Composition: Molecular Weight = 246.04 gm
   Arsenic  60.90 %  As
   Sulfur   39.10 %  S
           ______ 
           100.00 % 
Help on Empirical Formula: Empirical Formula: As2S3
Help on Environment: Environment: Low temperature hydrothermal veins, hot springs, and fumaroles; also commony as an alteration product of arsenic minerals, especially realgar.
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1747
Help on Locality: Locality: Common world wide. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: From the Latin, auripigmentum, in allusion to the vivid golden hue.
Help on Synonym: Synonym: ICSD 15239
  PDF 24-75
 

Orpiment Image

Click Here for Larger Orpiment Image in a New Browser Window Images:
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Orpiment

Comments: Deep orange-colored orpiment crystal aggregate.
Location: Twin Creeks mine, 62 bench, north of Winnemucca, Humboldt County, Nevada. USA. Scale: 6.5 x 5.5 cm.
© Fabre Minerals

Orpiment Crystallography
Help on Axial Ratios: Axial Ratios: a:b:c =1.1981:1:0.4431
Help on Cell Dimensions: Cell Dimensions: a = 11.49, b = 9.59, c = 4.25, Z = 4; beta = 90.45° V = 468.29 Den(Calc)= 3.49
Help on Crystal System: Crystal System: Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 21/n
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 4.82(1), 2.7(0.53), 4(0.47),
Help on Forms: Forms:

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Forms: [ 0 1 0] [ 1 2 0] [ 1 1 1] [ 1 0 1]

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Click Here for Large Orpiment Structure Window Crystal Structure:

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Mullen D J E , Nowacki W , Zeitschrift fur Kristallographie , 136 (1972) p.48-65, Refinement of the crystal structures of realgar, AsS and orpiment, As2S3, Locality: Lengenbach quarry, Binnatal, Switzerland

 

Physical Properties of Orpiment

Help on Cleavage: Cleavage: [010] Perfect
Help on Color: Color: Lemon yellow, Brownish yellow, Orange yellow.
Help on Density: Density: 3.49 - 3.56, Average = 3.52
Help on Diaphaniety: Diaphaniety: Transparent to translucent
Help on Fracture: Fracture: Sectile - Curved shavings or scrapings produced by a knife blade, (e.g. graphite).
Help on Habit: Habit: Foliated - Two dimensional platy forms.
Help on Habit: Habit: Massive - Fibrous - Distinctly fibrous fine-grained forms.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Hardness: Hardness: 1.5-2 - Talc-Gypsum
Help on Luminescence: Luminescence: None.
Help on Luster: Luster: Pearly
Help on Streak: Streak: pale yellow
 

Optical Properties of Orpiment

Help on Optical Data: Optical Data: Biaxial (-), a=2.4, b=2.81, g=3.02, bire=0.6200, 2V(Calc)=62, 2V(Meas)=76. Dispersion r > v strong.
Help on Pleochroism (x): Pleochroism (x): yellow.
Help on Pleochroism (y): Pleochroism (y): yellow.
Help on Pleochroism (z): Pleochroism (z): greenish yellow.
Help on RL Anisotrophism: RL Anisotrophism: Bearly observable because of the strong internal reflections.
Help on RL Pleochroism: RL Pleochroism: Strong, white to gray-white with a reddish tint.
Help on Reflectivity Reflectivity
Standardized Intensity (100%) Reflection Spectra of Orpiment in Air
λ R1 R2  ∑ R1(λ)   ∑ R2(λ) 
 400 nm   29.80   39.90 
   
 420 nm   27.60   36.80 
 440 nm   25.40   33.70 
 460 nm   23.60   31.20 
 480 nm   22.30   29.50 
 500 nm   21.40   28.40 
 520 nm   20.90   27.70 
 540 nm   20.50   27.20 
 560 nm   20.10   26.70 
 580 nm   19.70   26.40 
 600 nm   19.40   25.90 
 620 nm   19.10   25.60 
 640 nm   19.00   25.40 
 660 nm   18.80   25.20 
 680 nm   18.70   25.10 
 700 nm   18.60   25.00 
Calculated Relative Intensity Colors of Orpiment in Air
Relative
Intensity		    0%   50% 100% 150% 200% 250% 300% 350% 400% 440%
R1                    
R2                    
 

Calculated Properties of Orpiment

Help on Electron Density: Electron Density:

relectron=3.23 gm/cc
note: rOrpiment =3.49 gm/cc.
Help on Fermion Index Fermion Index Fermion Index = 0.00293
Boson Index = 0.99707
Help on Photoelectric: Photoelectric:

PEOrpiment = 44.66 barns/electron
U=PEOrpiment x relectron= 144.44 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Orpiment is Not Radioactive
 

Orpiment Classification
Help on Dana Class: Dana Class: 2.11.1.1 (2)Sulfides - Including Selenides and Tellurides
  (2.11)where Am Bn Xp, with (m+n):p=2:3
  (2.11.1)Dana Group
 
2.11.1.1 Orpiment As2S3 P 21/n 2/m
 
2.11.1.2 Getchellite AsSbS3 P 21/a 2/m
Help on Strunz Class: Strunz Class: II/F.02-70 II - Sulfides and sulphosalts
  II/F - Sulfides with nonmetallic properties, Arsenic-Sulfides
  II/F.02 - Duranusite - Jeromite series
 
II/F.02-10 Duranusite As4S Unk Ortho
 
II/F.02-20 Dimorphite As4S3 P nma 2/m 2/m 2/m
 
II/F.02-30 Realgar AsS P 21/n 2/m
 
II/F.02-40 Pararealgar AsS P 21/c 2/m
 
II/F.02-50 Alacranite As8S9 P 2/c 2/m
 
II/F.02-60 Uzonite As4S5 P 21/m 2/m
 
II/F.02-70 Orpiment As2S3 P 21/n 2/m
 
II/F.02-80 Laphamite As2(Se,S)3 P 21/n 2/m
 
II/F.02-90 Jeromite As(S,Se)2 None
 

Other Orpiment Information
Help on References: References: NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)
Help on See Also: See Also: Links to other databases for Orpiment :
1 -Am. Min. Crystal Structure Database 2 - Amethyst Galleries' Mineral Gallery 3 - Applied Mineralogy 4 -Athena 5 - Crocoite.com Mineral Locations 6 - EUROmin Project 7 -Google Images 8 -Google Scholar 9 -Handbook of Mineralogy (UofA) 10 -MinDAT 11 -MinMax(Deutsch) 12 -MinMax(English) 13 -Mineralienatlas (Deutsch) 14 - Philatelic Mineralogy 15 -QUT Mineral Atlas 16 - University of Manchester - Mineral Structure 17 - WWW-MINCRYST 18 -theimage 19 -École des Mines de Paris

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Orpiment

As2S3
Dana No: 2.11.1.1 Strunz No: II/F.02-70
Locality:

 

Notes:

 
 
   
 
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