from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A soft orange-red arsenic ore, As2S2, used in pyrotechnics and tanning and as a pigment.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A mineral, arsenic sulfide (AsS), often associated with orpiment and stibnite in lead, silver and gold ores.
from the GNU version of the Collaborative International Dictionary of English
- n. Arsenic sulphide, a mineral of a brilliant red color; red orpiment. It is also an artificial product.
from The Century Dictionary and Cyclopedia
- n. 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.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a rare soft orange mineral consisting of arsenic sulphide; an important ore of arsenic
Several other, less-common minerals contain arsenic, including orpiment, realgar, and enargite, which are arsenic sulfides.
Among the items quickly snapped up was an exquisite orange and yellow glass piece made to imitate realgar, a poisonous mineral that is almost pure sulphide of arsenic, beautiful to the eye but poisonous to the touch (price: around €2,000).
Such are the kinds of stones that cannot be melted, and realgar, and ochre, and ruddle, and sulphur, and the other things of that kind, most
Mix together realgar and orpiment; some object to this mixture on account of the poisonous nature of the ingredients.
This is procured by mixing massicot, or Naples yellow, with a small quantity of realgar, and a very little Spanish white.
~ Arsenic occurs in considerable quantities in nature as the native element, as the sulphides realgar (As_ S_ ) and orpiment
Orange-coloured grounds may be formed by mixing vermilion or red lead with King's yellow, or orange lake or red orpiment (? realgar) will make a brighter orange ground than can be produced by any mixture.
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.
It occurs as metallic arsenic, which is of a steel-grey colour, brittle, and gives off a garlic-like odour when heated; as arsenious acid; in the form of two sulphides -- the red sulphide, or realgar, and the yellow sulphide, or orpiment; and as arsenite of copper, or Scheele's green.
The orange-red sulphides of arsenic, orpiment and realgar, are formed both as primary minerals of igneous source and as secondary products of weathering.