keffekiliten.
Etymology: < keffekill n. + -ite suffix1: named (in German form keffekilith) by Fischer 1811.Previous versions of the OED give the stress as: ˈkeffekilite.
Mineralogy.
1868 in J. D. Dana (ed. 5)
This entry has not yet been fully updated (first published 1901; most recently modified version published online September 2019).