realgar

re·al·gar  (r-lgär, -gr)

n.

A soft orange-red arsenic ore, As₂S₂, used in pyrotechnics and tanning and as a pigment.

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[Middle English, from Medieval Latin, from Catalan, from Arabic rahj al-r, powder (of) the mine or cave : rahj, powder + al-, the + r, cave; see rr in Semitic roots.]

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realgar [rɪˈælgə]

n

(Earth Sciences / Minerals) 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

[via Medieval Latin from Arabic rahj al-ghar powder of the mine]

Thesaurus

Noun

1.

realgar - a rare soft orange mineral consisting of arsenic sulphide; an important ore of arsenic As, atomic number 33, arsenic - a very poisonous metallic element that has three allotropic forms; arsenic and arsenic compounds are used as herbicides and insecticides and various alloys; found in arsenopyrite and orpiment and realgar mineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition