Definition of marcylite in US English:

marcylite

noun

Mineralogy
  • An impure or altered form of copper sulphide from the Red River district of Louisiana.

Origin

Mid 19th century; earliest use found in Randolph Benton Marcy (1812–1887). From the name of General Randolph Barnes Marcy + -lite.

Pronunciation

marcylite

/ˈmɑːsɪlʌɪt/