quartz

From German Quarz, from Middle High German (Central East German) quarz, twarc, from a West Slavic language [compare Polish twardy (“hard”), Czech tvrdý (“hard”)], from Proto-Slavic *tvьrdъ ultimately from Proto-Indo-European *twerH- (“to enclose, grab”).

出典: Wiktionary「quartz」（CC BY-SA 4.0）