kermesite
/kərˈmɛs.aɪt/Definitions
1. noun
A reddish-brown mineral, a hydrated arsenic sulfide, As2S3·nH2O.
“The geologist identified kermesite as a key component of the ancient ore deposits.”
2. noun
A bright red pigment, originally obtained from the kermes insect.
“In medieval art, kermesite was a highly prized colorant used for painting.”