realgar

American  

[ree-al-ger, -gahr] / riˈæl gər, -gɑr /

noun

1. arsenic disulfide, As 2 S 2 , found in nature as an orange-red mineral and also produced artificially: used in pyrotechnics.

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realgar British  

/ rɪˈælɡə /

noun

1. a rare orange-red soft mineral consisting of arsenic sulphide in monoclinic crystalline form. It occurs in Utah and Romania and as a deposit from hot springs. It is an important ore of arsenic and is also used as a pigment. Formula: AsS

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Etymology

Origin of realgar

1350–1400; Middle English < Medieval Latin realger ≪ Arabic rahj al-ghār powder of the mine or cave

Example Sentences

I stuck my head inside a cabinet to get a close look at the rocks of the arsenic sulfides realgar and orpiment, blazes of flame orange locked within the crystals.

From The New Yorker • Aug. 27, 2018

Many substances were employed in ancient medicine: galena was the basis of a valuable Egyptian cosmetic and drug; the arsenic sulphides, realgar and orpiment, litharge, alum, saltpetre, iron rust were also used.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" by Various

The orange-red sulphides of arsenic, orpiment and realgar, are formed both as primary minerals of igneous source and as secondary products of weathering.

From The Economic Aspect of Geology by Leith, C. K. (Charles Kenneth)

Take of nitrate of baryta, twenty-seven parts, by weight; of sulphur, thirteen; of chloride of potassa, five; of realgar, two; and of charcoal three parts.

From Home Pastimes; or Tableaux Vivants by Head, James H.

Before the Bp. on Ch. behaves like realgar, but in an ignition tube it gives a dark yellow sublimate which is transparent.

From The Elements of Blowpipe Analysis by Getman, Frederick Hutton