Orpiment crystal from Twin Creeks Mine, Potosi District, Humboldt County, Nevada, United States (Size: 3.3 cm × 2.1 cm × 2.1 cm)
General
Category
Sulfide mineral
Formula (repeating unit)
As2S3
IMA symbol
Orp[1]
Strunz classification
2.FA.30
Crystal system
Monoclinic
Crystal class
Prismatic (2/m) (same H-M symbol)
Space group
P21/n
Unit cell
a = 11.475(5), b = 9.577(4) c = 4.256(2) [Å], β = 90.45(5)°; Z = 4
Identification
Color
Lemon-yellow to golden or brownish yellow
Crystal habit
Commonly in foliated columnar or fibrous aggregates; may be reniform or botryoidal; also granular or powdery; rarely as prismatic crystals
Twinning
On {100}
Cleavage
Perfect on {010}, imperfect on {100};
Tenacity
Sectile
Mohs scale hardness
1.5–2
Luster
Resinous, pearly on cleavage surface
Streak
Pale lemon-yellow
Diaphaneity
Transparent
Specific gravity
3.49
Optical properties
Biaxial (−)
Refractive index
nα = 2.400 nβ = 2.810 nγ = 3.020
Birefringence
δ = 0.620
Pleochroism
In reflected light, strong, white to pale gray with reddish tint; in transmitted light, Y = yellow, Z = greenish yellow
2V angle
Measured: 30° to 76°, Calculated: 62°
Dispersion
r > v, strong
References
[2][3][4]
Orpiment, also known as ″yellow arsenic blende″ is a deep-colored, orange-yellow arsenic sulfide mineral with formula As 2S 3. It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and may be formed through sublimation.
Orpiment takes its name from the Latin auripigmentum (aurum, "gold" + pigmentum, "pigment"), due to its deep-yellow color. Orpiment once was widely used in artworks, medicine, and other applications. Because of its toxicity and instability, its usage has declined.
^Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Orpiment" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 14 March 2022.
Orpiment, also known as ″yellow arsenic blende″ is a deep-colored, orange-yellow arsenic sulfide mineral with formula As 2S 3. It is found in volcanic...
compact, or powdery form, often in association with the related mineral, orpiment (As2S3). It is orange-red in color, melts at 320 °C, and burns with a bluish...
in France has a painting of a yellow horse 17,000 years old. Ochre and orpiment pigments were used to represent gold and skin color in Egyptian tombs,...
ore minerals — orpiment and realgar,: 135, 239, 438 in composition — arsenic sulfides. Both of these minerals, realgar and orpiment, have been mined...
Paul A Dictionary of Color New York:1930 McGraw-Hill Page 201 (See under Orpiment [a synonym of the color name Royal Yellow] ); color sample of Royal Yellow:...
'the orpiment', based on Persian zar ("gold") from the word زرنيخ zarnikh, meaning "yellow" (literally "gold-colored") and hence "(yellow) orpiment". It...
lake, azurite, ultramarine, yellow lake and lead-tin-yellow. Synthetic orpiment was shown in the shadows of the sleeve of the jewish groom. This toxic...
yellow solid that is insoluble in water. It also occurs as the mineral orpiment (Latin: auripigmentum), which has been used as a pigment called King's...
Commonly found as small octahedra it is white, but impurities of realgar or orpiment may give it a pink or yellow hue. It can be associated with its dimorph...
discovered a chemical depilatory made from a mixture of lime and water and orpiment (arsenic trisulfide). "Hair Preparations", Ullmann's Encyclopedia of Industrial...
Stibnite occurs in hydrothermal deposits and is associated with realgar, orpiment, cinnabar, galena, pyrite, marcasite, arsenopyrite, cervantite, stibiconite...
Greek Theophrastus recognized the arsenic minerals called realgar and orpiment. Elemental arsenic was discovered in the 13th century by Albertus Magnus...
Arsenic sulfide may refer to: Arsenic trisulfide, As2S3, the mineral orpiment Arsenic pentasulfide, As2S5, similar structure to phosphorus pentasulfide...
and arsenic vapor. With 46% arsenic content, arsenopyrite, along with orpiment, is a principal ore of arsenic. When deposits of arsenopyrite become exposed...
siliceous geothermal fluid is oversaturated with metalloid compounds such as orpiment (As2S3) and stibnite (Sb2S3), which precipitate and form orange subaqueous...
substances like salts, atramenta (iron sulfate), alums, vitriol, arsenic, orpiment, sulfur, and similar substances that were not metallic bodies. The term...
yellow, ochres, and azurite, he also used the rare pigments realgar and orpiment. Titian's wife, Cecilia, was a barber's daughter from his hometown village...
Orl Otjisumeite Otj Oxynatromicrolite Onmic Offretite Off Omeiite Ome Orpiment Orp Ottemannite Ott Oxyphlogopite Ophl Oftedalite Oft Ominelite Omi Orschallite...
silver till it liquefies and then cooling. King's yellow – formed by mixing orpiment with white arsenic. Lapis solaris (Bologna stone) – barium sulfide – 1603...
pigments used by medieval painters, such as cinnabar (contains mercury), orpiment (contains arsenic), or lead white (contains lead) are highly toxic. Most...
recent examples (chromium and cadmium). Arsenic, as realgar (As 4S 4) and orpiment (As 2S 3), was known in ancient times. Strabo (64–50 BCE – c. AD 24?),...
paste consisted of an admixture of slaked lime, water, wood-ash and yellow orpiment (arsenic trisulfide); In rural India and Iran, where this mixture is called...
part of Twin Creek, was first identified in the 1980s. A rare specimen of orpiment discovered in the mine was donated to the Smithsonian. In 1911, the Battle...
including: Ochre, an earth pigment that occurs as the mineral limonite; and Orpiment, chemically arsenic trisulfide, As2S3. Green Verdigris, chemically cupric...
usual pigments of the renaissance period such as malachite mixed with orpiment in the green drapery on top of the painting, natural ultramarine mixed...
it is a Mediterranean text and the pigments used in making it include orpiment, a yellow made from arsenic sulphide, exported from Italy, where it is...
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