montmartrite
/mɒntˈmɑːtrʌɪt/ /ˌmɒ̃ˈmɑːtrʌɪt/Mineralogy. Now historical
noun
A variety of gypsum containing calcium carbonate.
Origin
Early 19th century; earliest use found in Andrew Ure (1778–1857), chemist. From French montmartrite from Montmartre, the name of a hill and suburb of Paris, the mineral's locality + -ite.