Pararealgar is an arsenic sulfide mineral with the chemical formula As4S4,[3] also represented as AsS.

It is soft with a Mohs hardness of 1 - 1.5, is yellow orange in colour, and its monoclinic prismatic crystals are very brittle, easily crumbling to powder.

Both isomers of As4S4 are molecular, in contrast to the other main sulfide of arsenic, orpiment (As2S3), which is polymeric.

[7] Pararealgar occurs as an alteration product of realgar in stibnite-bearing quartz veins typically as a result of exposure to light.

Pararealgar is an alteration product of realgar resulting from exposure to light.