quartz
n. uncountablen. a hard, shiny mineral found in many types of rocks. It is often used to make glass or parts for watches because it is very strong and stable.
n. a hard mineral consisting of silica, found widely in igneous, metamorphic, and sedimentary rocks. It is often used in electronics and timekeeping due to its piezoelectric properties.
The watch uses a tiny piece of quartz to keep time.
Geologists found large veins of white quartz running through the granite cliffs near the shore.
The precision of modern timekeeping relies on the consistent vibration of quartz crystals when an electric current is applied, a phenomenon that revolutionized the horological industry.
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”).
Uncountable when referring to the mineral substance; countable when referring to specific varieties or individual crystals.