The deterioration of realgar was thought to produce the closely related yellow orpiment , but this was recently proven to be false and the deterioration product is in fact yellow-orange pararealgar. In old paintings and manuscripts, realgar was a common pigment for paints and dyes. Many of these paintings now have a yellow or orange hue where once the color must have been an original red. Color is orange to red. Luster is resinous, adamantine to sub-metallic.
Crystals are translucent to transparent.
They are terminated by a wedge-like dome. Also found as grains, crusts and earthy masses. Cleavage is good in one direction. Fracture is subconchoidal. Associated Minerals almost always include orpiment , also calcite , stibnite and other metal sulfide ores.