malladrite
/ˈmalədrʌɪt/Mineralogy
noun
A trigonal fluosilicate of sodium, Na2SiF6, occurring as pale rose-coloured crusts on lava.
Origin
1920s; earliest use found in Mineralogical Abstracts. From Italian malladrite from the name of Alessandro Malladra, Italian director of the Vesuvius Observatory + -ite.