• WordNet 3.6
    • n realgar a rare soft orange mineral consisting of arsenic sulphide; an important ore of arsenic
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Webster's Revised Unabridged Dictionary
    • n Realgar (Min) Arsenic sulphide, a mineral of a brilliant red color; red orpiment. It is also an artificial product.
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Century Dictionary and Cyclopedia
    • n realgar Arsenic disulphid (As2S2), a combination of an equal number of sulphur and arsenic atoms; red sulphuret of arsenic, which is found native in transparent crystals, and also massive. Realgar differs from orpiment in that orpiment is composed of two equivalents of arsenic and three of sulphur, and has a yellow color. Realgar, also called red arsenic or ruby sulphur, is prepared artificially for use as a pigment and for making white fire, which is a mixture of 2 parts of ruby sulphur and 10 parts of niter.
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Chambers's Twentieth Century Dictionary
    • n Realgar rē-al′gar a native sulphuret of arsenic, a mineral consisting of about 70 parts of arsenic and 30 of sulphur, and of a brilliant red colour.
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Webster's Revised Unabridged Dictionary
F. réalgar, Sp. rejalgar, Ar. rahj al ghār, powder of the mine
Chambers's Twentieth Century Dictionary
Fr.,—Ar. rahj-al-ghar, 'powder of the mine.'


In literature:

Then his wife untied him, carried him to bed, and gave him wine mingled with realgar to drink.
"The Chinese Fairy Book" by Various
Silver silver Arsenic arsenic Orpiment, realgar.
"Elements of Chemistry," by Antoine Lavoisier
Combined with sulphur it forms orpiment and realgar, which are the yellow and red sulphides of arsenic.
"The New Gresham Encyclopedia. Vol. 1 Part 2" by Various
There are three known compounds of arsenic and sulphur, namely, realgar As2S2, orpiment As2S3, and arsenic pentasulphide As2S5.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 6" by Various
Arsenic, in its well-known and beautiful forms, orpiment and realgar, is found in New South Wales and Victoria.
"Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 8" by Various
Orpiment and realgar are used as pigments.
"Heads of Lectures on a Course of Experimental Philosophy: Particularly Including Chemistry" by Joseph Priestley
To the unctuous juices belong these species: sulphur, bitumen, realgar and orpiment.
"De Re Metallica" by Georgius Agricola

In science:

Pb, may be determined independently, by measuring the lead-205 content in the coexisting minerals, the realgar and the orpiment). Thus, if the mineral would be available from a couple of different depths, this could solve all the otherwise serious background problems. If this is realistic remains to be seen.
The Neutrino - Its Past, Present and Future