Realgar
A valid IMA mineral species - grandfathered
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About Realgar
Formula:
As4S4
Colour:
Dark red to orange-red
Lustre:
Resinous, Greasy
Hardness:
1½ - 2
Specific Gravity:
3.56
Crystal System:
Monoclinic
Name:
From Arabic "rahj al-gahr", powder of the mine. Known as a mineral pigment in Byzantium (essentially Asia Minor and the Balkan Peninsula) at least by the beginning of the thirteenth century and presumably having a name by that time. An old realgar locality on the Balkan Peninsula is found at Allchar, Republic of Macedonia.
Alters to pararealgar on exposure to light.
Visually similar to sarabauite and other red arsenic-sulphur minerals.
Visit gemdat.org for gemological information about Realgar.
Visually similar to sarabauite and other red arsenic-sulphur minerals.
Visit gemdat.org for gemological information about Realgar.Unique Identifiers
Mindat ID:
3375
Long-form identifier:
mindat:1:1:3375:2
IMA Classification of Realgar
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
AsS
Type description reference:
Classification of Realgar
2.FA.15a
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
A : With As, (Sb), S
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
A : With As, (Sb), S
2.8.21.1
2 : SULFIDES
8 : AmXp, with m:p = 1:1
2 : SULFIDES
8 : AmXp, with m:p = 1:1
3.7.4
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
7 : Sulphides etc. of V, As, Sb and Bi
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
7 : Sulphides etc. of V, As, Sb and Bi
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Rlg | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Rlg | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Rgr | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Realgar
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Realgar
Resinous, Greasy
Transparency:
Transparent
Colour:
Dark red to orange-red
Streak:
Orange-red to red
Hardness:
1½ - 2 on Mohs scale
Tenacity:
Sectile
Cleavage:
Distinct/Good
Good on {010}, less good on {100}, {101}, {120}, {110}
Good on {010}, less good on {100}, {101}, {120}, {110}
Density:
3.56 g/cm3 (Measured) 3.59 g/cm3 (Calculated)
Optical Data of Realgar
Type:
Biaxial (-)
RI values:
nα = 2.538 nβ = 2.684 nγ = 2.704
2V:
Measured: 40° , Calculated: 38°
Max. Birefringence:
δ = 0.166
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Anisotropism:
Strong.
Dispersion:
Relatively strong.
Reflectivity:
| Wavelength | R1 (%) |
|---|---|
| 400nm | 29.9% |
| 420nm | 28.6% |
| 440nm | 27.4% |
| 460nm | 26.3% |
| 480nm | 25.2% |
| 500nm | 24.2% |
| 520nm | 23.3% |
| 540nm | 22.4% |
| 560nm | 21.7% |
| 580nm | 21.1% |
| 600nm | 20.6% |
| 620nm | 20.3% |
| 640nm | 20.0% |
| 660nm | 19.7% |
| 680nm | 19.5% |
| 700nm | 19.3% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 29.9%.
Colour in reflected light:
Gray white.
Internal Reflections:
Yellow to red.
Pleochroism:
Visible
Comments:
Nearly colourless to pale golden yellow.
Chemistry of Realgar
Mindat Formula:
As4S4
Elements listed:
Crystallography of Realgar
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 9.325(3) Å, b = 13.571(5) Å, c = 6.587(3) Å
β = 106.43°
β = 106.43°
Ratio:
a:b:c = 0.687 : 1 : 0.485
Unit Cell V:
799.54 ų (Calculated from Unit Cell)
Z:
16
Morphology:
Prismatic
Twinning:
Contact twins on {100}
Comment:
Space Group: P21/n.
Crystallographic forms of Realgar
Crystal Atlas:
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Realgar no.33 - {110} - Goldschmidt (1913-1926)
Realgar - Highly modified
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Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0004882 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 |  | 2009 | synthetic | 0 | 293 |
| 0004877 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004874 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004873 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004872 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004871 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004870 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004869 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004868 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004867 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004866 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004865 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004864 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004863 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004862 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004861 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004860 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004859 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004858 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004857 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0004856 | Realgar | Kyono A (2009) Molecular conformation and anion configuration variations for As4S4 and As4Se4 in an anion-substituted solid solution American Mineralogist 94 451-460 | | 2009 | synthetic | 0 | 293 |
| 0010732 | Realgar | Mullen D J E, Nowacki W (1972) Refinement of the crystal structures of realgar, AsS and orpiment, As2S3 Zeitschrift fur Kristallographie 136 48-65 | | 1972 | Lengenbach quarry, Binnatal, Switzerland | 0 | 293 |
| 0009149 | Realgar | Ito T, Morimoto N, Sadanaga R (1952) The crystal structure of realgar Acta Crystallographica 5 775-782 |  | 1952 | Saimoko, Japan | 0 | 293 |
| 0003937 | Realgar | Kyono A, Kimata M, Hatta T (2005) Light-induced degradation dynamics in realgar: in situ structural investigation using single crystal X-ray diffraction and X-ray photoelectron spectroscopy American Mineralogist 90 1563-1570 | | 2005 | 0 | 293 | |
| 0003936 | Realgar | Kyono A, Kimata M, Hatta T (2005) Light-induced degradation dynamics in realgar: in situ structural investigation using single crystal X-ray diffraction and X-ray photoelectron spectroscopy American Mineralogist 90 1563-1570 | | 2005 | 0 | 293 | |
| 0003935 | Realgar | Kyono A, Kimata M, Hatta T (2005) Light-induced degradation dynamics in realgar: in situ structural investigation using single crystal X-ray diffraction and X-ray photoelectron spectroscopy American Mineralogist 90 1563-1570 | | 2005 | 0 | 293 | |
| 0003934 | Realgar | Kyono A, Kimata M, Hatta T (2005) Light-induced degradation dynamics in realgar: in situ structural investigation using single crystal X-ray diffraction and X-ray photoelectron spectroscopy American Mineralogist 90 1563-1570 | | 2005 | 0 | 293 | |
| 0003933 | Realgar | Kyono A, Kimata M, Hatta T (2005) Light-induced degradation dynamics in realgar: in situ structural investigation using single crystal X-ray diffraction and X-ray photoelectron spectroscopy American Mineralogist 90 1563-1570 | | 2005 | 0 | 293 | |
| 0011671 | Realgar | Wyckoff R W G (1963) Second edition. Interscience Publishers, New York, New York Crystal Structures 1 85-237 | 1963 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.40 Å | (100) |
| 3.19 Å | (90) |
| 2.94 Å | (80) |
| 2.73 Å | (80) |
| 1.859 Å | (60) |
| 2.49 Å | (50) |
| 2.14 Å | (50) |
Comments:
Allchar, Macedonia.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 11 : Volcanic fumarole minerals; reduced phases (see also #45) | |
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 12 : Hadean hydrothermal subsurface sulfide deposits (see also #33) | |
| 14 : Hot springs, geysers, and other subaerial geothermal minerals | |
| Near-surface Processes | |
| 24 : Authigenic minerals in terrestrial sediments (see also #17) | |
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Synonyms of Realgar
Other Language Names for Realgar
Catalan:Realgar
Czech:Realgar
Dutch:Realgaar
French:Réalgar
Arsenic Rouge
Arsenic Rouge
Hungarian:Realgár
Italian:Realgar
Japanese:鶏冠石
Lithuanian:Realgaras
Low Saxon/Low German:Realgar
Polish:Realgar
Portuguese:Realgar
Romanian:Realgar
Russian:Реальгар
Simplified Chinese:雄黄
Slovak:Realgár
Spanish:Rejalgar
Eolita
Realgarita
Eolita
Realgarita
Swedish:Realgar
Common Associates
Associations Based on Photo Data:
| 613 photos of Realgar associated with Orpiment | As2S3 |
| 387 photos of Realgar associated with Calcite | CaCO3 |
| 313 photos of Realgar associated with Quartz | SiO2 |
| 193 photos of Realgar associated with Pyrite | FeS2 |
| 191 photos of Realgar associated with Stibnite | Sb2S3 |
| 189 photos of Realgar associated with Native Arsenic | As |
| 186 photos of Realgar associated with Baryte | BaSO4 |
| 127 photos of Realgar associated with Pararealgar | As4S4 |
| 103 photos of Realgar associated with Sphalerite | ZnS |
| 84 photos of Realgar associated with Dolomite | CaMg(CO3)2 |
Related Minerals - Strunz-mindat Grouping
| 2.FA. | Bonazziite | As4S4 |
| 2.FA. | Anorpiment | As2S3 |
| 2.FA. | Paradimorphite | As4S3 |
| 2.FA.05 | Duranusite | As4S |
| 2.FA.10 | Dimorphite | As4S3 |
| 2.FA.15b | Pararealgar | As4S4 |
| 2.FA.15d | 'UM1970-18-S:As' | As4S4 |
| 2.FA.20 | Alacránite | As8S9 |
| 2.FA.25 | Uzonite | As4S5 |
| 2.FA.30 | Laphamite | As2Se3 |
| 2.FA.30 | Orpiment | As2S3 |
| 2.FA.35 | Getchellite | AsSbS3 |
| 2.FA.40 | Wakabayashilite | [(As,Sb)6S9][As4S5] |
| 2.FA.40 | Kalgoorlieite | As2Te3 |
Other Information
Thermal Behaviour:
Heated in a closed tube, it melts, volatilizes, and gives a transparent red sublimate. Heating slowly in an open tube, it gives sulphurous fumes and a white crystalline sublimate.
Notes:
Soluble in caustic alkalies.
Special Storage/
Display Requirements:
Display Requirements:
Decomposes to orange pararealgar with exposure to light.
Health Risks:
Contains arsenic - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest.
Internet Links for Realgar
mindat.org URL:
https://www.mindat.org/min-3375.html
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References for Realgar
Reference List:
Ito, T., Morimoto, N., Sadanaga, R. (1952) The crystal structure of realgar. Acta Crystallographica, 5 (6) 775-782 doi:10.1107/s0365110x52002112
Forneris, Roberto (1969) The infrared and Raman spectra of realgar and orpiment. American Mineralogist, 54 (7-8) 1062-1074
Scheuermann, W., Ritter, G. J. (1969) Raman Spectra of Cinnabar (HgS), Realgar (As4S4) and Orpiment (As2S3). Zeitschrift für Naturforschung A, 24 (3). 408-411 doi:10.1515/zna-1969-0317
Yu, Shu-Cheng, Zoltai, Tibor (1972) Crystallography of a high-temperature phase of realgar. American Mineralogist, 57 (11-12) 1873-1875
Mullen, D. J. E.; Nowacki, W. (1972) Refinement of the crystal structures of realgar, AsS and orpiment, As2S3. Zeitschrift für Kristallographie, 136 (1-2). 48-65 doi:10.1524/zkri.1972.136.1-2.48
Criddle, A. J., Stanley, C. J. (1993) Data file. In Quantitative Data File for Ore Minerals. Springer Netherlands. p.1-635. doi:10.1007/978-94-011-1486-8_1p.477
Frost, R. L., Martens, W. N., Kloprogge, J. T. (2002) Raman spectroscopic study of cinnabar (HgS), realgar (As4S4), and orpiment (As2S3) at 298 and 77K. Neues Jahrbuch für Mineralogie - Monatshefte, 2002 (10) 469-480 doi:10.1127/0028-3649/2002/2002-0469
Kyono, A. (2005) Light-induced degradation dynamics in realgar: in situ structural investigation using single-crystal X-ray diffraction study and X-ray photoelectron spectroscopy. American Mineralogist, 90 (10) 1563-1570 doi:10.2138/am.2005.1785
Bonazzi, Paola, Bindi, Luca (2008) A crystallographic review of arsenic sulfides: effects of chemical variations and changes induced by exposure to light. Zeitschrift für Kristallographie - Crystalline Materials, 223 (1). 132-147 doi:10.1524/zkri.2008.0011
Localities for Realgar
Showing 920 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
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No. 5 Mine, Baia Sprie, Maramureș County, Romania