from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A mineral, Ag3AsS3, often found with pyragyrite in silver veins.
from the GNU version of the Collaborative International Dictionary of English
- n. A sulphide of arsenic and silver of a beautiful cochineal-red color, occurring in rhombohedral crystals, and also massive; ruby silver.
from The Century Dictionary and Cyclopedia
- n. A native sulphid of arsenic and silver, occurring in rhombohedral and scalenohedral crystals and also massive.
Named after French chemist Joseph L. Proust (1754-1826) in 1832. (Wiktionary)