| Name: | Orpiment |
| Derivation: | From "aurum pigmentum" (Latin) gold pigment |
| Formula: | As2S3 |
| Description: | Bright yellow. If exposed to light, it tends to turn red. You can see red bits in the specimen. |
Orpiment used to be used as a pigment. It is an ore of Arsenic, which is famous in detective novels as a poison! Ratsbane, used obviously to kill rats, is an Arsenic compound.
Today, Arsenic is used in semi-conductors.