orpiment
noun
or·pi·ment ˈȯr-pə-mənt 
: a rare orange to lemon-yellow mineral consisting of a native trisulfide of arsenic
Example Sentences
Recent Examples on the Web Medieval painters used a variety of pigments, some of which were quite toxic (cinnabar, orpiment, and lead white in particular). 
Jennifer Ouellette, Ars Technica, 3 Dec. 2021 Among the artifacts found in the cave was orpiment, a pigment from eastern Turkey used for decorative purposes, and 63 beads, some of which came from as far away as Baghdad. Livia Gershon, Smithsonian Magazine, 29 Apr. 2021
Jennifer Ouellette, Ars Technica, 3 Dec. 2021 Among the artifacts found in the cave was orpiment, a pigment from eastern Turkey used for decorative purposes, and 63 beads, some of which came from as far away as Baghdad. Livia Gershon, Smithsonian Magazine, 29 Apr. 2021 Word History
Etymology
Middle English, from Anglo-French, from Latin auripigmentum, from aurum + pigmentum pigment
First Known Use
14th century, in the meaning defined above