Definition of nontronite in English:

nontronite

noun

Mineralogy
  • A pale yellow or greenish crystalline clay mineral, Na₀.₃₃Fe₂ 3+(Si,Al)₄O₁₀(OH)₂, belonging to the smectite or montmorillonite group and sometimes resembling opal.

Origin

Mid 19th century; earliest use found in Charles Shepard (1804–1886). From French nontronite from Nontron, the name of the town in Dordogne, France, where the mineral was first found + -ite.

Pronunciation

nontronite

/ˈnɒntrənʌɪt/