AskDefine | Define orpiment

Dictionary Definition

orpiment n : a yellow mineral occuring in conjunction with realgar; an ore of arsenic

User Contributed Dictionary

English

Alternative spellings

Etymology

Old French, from Latin auripigmentum, from aurum ‘gold’ + pigmentum ‘pigment’.

Pronunciation

IPA: /'ɔ:pɪmənt/

Noun

orpiment (uncountable)
  1. arsenic trisulphide, occuring naturally in crystals or massive deposits, formerly used as a dye or pigment

Extensive Definition

Orpiment, As2S3, is a common monoclinic arsenic sulfide mineral. It has a Mohs hardness of 1.5 to 2 and a specific gravity of 3.46. It melts at 300 °C to 325 °C. Optically it is biaxial (−) with refractive indices of a=2.4, b=2.81, g=3.02.
Orpiment is an orange to yellow mineral that is found worldwide, and occurs as a sublimation product in volcanic fumaroles, low temperature hydrothermal veins, hot springs and as a byproduct of the decay of another arsenic mineral, realgar. It is often found in association with realgar. It takes its name from the Latin auripigmentum (aurum − gold + pigmentum − pigment) because of its deep yellow color.
Orpiment is also known as "King's Yellow", "Chinese Yellow" and "Yellow Orpiment" .

Historical uses

It was an important item of trade in the Roman Empire and was used as a medicine in China although it is highly toxic. It was also used as a fly poison and to poison arrows. Because of its striking color, it was also a favourite with alchemists searching for a way to make gold, both in China and the West.
Orpiment was ground, processed and used for centuries as a pigment in painting, being one of the few clear, bright yellow pigments available to artists up until the 19th century. Orpiment presented problems, however, such as its extreme toxicity and its incompatibility with other common pigments like lead and copper-based substances such as verdigris and azurite. The use of orpiment as a pigment matter ended almost entirely with the advent of the cadmium yellows and the various dye-based colors of the 19th century.

Contemporary uses

It is presently used in the production of infrared-transmitting glass, oil cloth, linoleum; in semiconductors and photoconductors, as a pigment and in fireworks. Mixed with two parts of slaked lime, orpiment is still very commonly used in rural India as a depilatory. It is also used in the tanning industry to remove hair from hides.

Crystal structure

Image gallery

References

  • The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals. 11th Edition. Ed. Susan Budavari. Merck & Co., Inc., N.J., U.S.A. 1989.
  • William Mesny. Mesny’s Chinese Miscellany. A Text Book of Notes on China and the Chinese. Shanghai. Vol. III, (1899), p. 251; Vol. IV, (1905), pp.26.

Footnotes

orpiment in Catalan: Orpiment
orpiment in German: Orpiment
orpiment in Estonian: Auripigment
orpiment in Spanish: Oropimente
orpiment in French: Orpiment
orpiment in Italian: Orpimento
orpiment in Lithuanian: Orpimentas
orpiment in Dutch: Orpiment
orpiment in Japanese: 雄黄
orpiment in Polish: Siarczek arsenu
orpiment in Slovak: Auripigment
orpiment in Ukrainian: Аурипігмент
orpiment in Chinese: 雌黄
Privacy Policy, About Us, Terms and Conditions, Contact Us
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2
Material from Wikipedia, Wiktionary, Dict
Valid HTML 4.01 Strict, Valid CSS Level 2.1