Definition of realgar in US English:



  • A soft reddish mineral consisting of arsenic sulfide, formerly used as a pigment and in fireworks.

    • ‘The next morning we drove west to the famous town of Shimen, the locality for all the superb realgar and orpiment crystals.’
    • ‘Unfortunately, however, many orpiment localities also contain abundant to trace realgar, sometimes intimately intergrown with the orpiment, leading to overall specimen stability problems.’
    • ‘Orpiment is a lesser mineral associated with realgar and lead sulfosalts in dolomite at Binnental, Valais, Switzerland.’
    • ‘Even the arsenic mine at Shimen, Hunan Province, is still the source of minor amounts of good realgar, orpiment, and calcite.’
    • ‘The specimen was a classic Lengenbach assemblage: sugary white dolomite matrix, realgar, minor pyrite, and a massive metallic gray sulfosalt that had been labeled as ‘sartorite.’’
    • ‘Other minerals associated with the orpiment crystals are white to colorless barite crystals, lemon-yellow crystalline masses of sulfur, and minor realgar.’
    • ‘Orpiment and realgar are yellow and orange mineral species of arsenic sulphide, used in 16th-century Venetian painting particularly, but at various other times also.’
    • ‘Small amounts of realgar have been reported from a large number of European occurrences, generally related to relatively recent volcanism, limestone or dolomite quarries, or base- and precious-metal deposits.’
    • ‘A number of relatively minor yet interesting California realgar localities are given by Murdoch and Webb.’
    • ‘It is an alteration product of realgar, native arsenic, and, less commonly, arsenopyrite.’


Late Middle English: via medieval Latin from Arabic rahj al-ġār ‘arsenic’, literally ‘dust of the cave’.