Ancylite is a group of hydrous strontium carbonate minerals containing cerium, lanthanum and minor amounts of other rare-earth elements. The chemical formula is Sr(Ce,La)(CO3)2(OH)·H2O with ancylite-Ce enriched in cerium and ancylite-La in lanthanum.
Ancylite was first described in 1899 for an occurrence in the Narsarsuk pegmatite in west Greenland and named from the Ancient Greek: ἀγκύλος for curved in reference to its rounded or distorted crystal form.
