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Quartz
01
colorless glass made of almost pure silica
02
a hard glossy mineral consisting of silicon dioxide in crystal form; present in most rocks (especially sandstone and granite); yellow sand is quartz with iron oxide impurities
Exemplo
Minerals like quartz and feldspar occur in many types of rocks.
As a crystallographer, she discovered a new form of quartz.
The geologist discovered veins of quartz impregnated with gold deposits deep within the earth.
Pendulum clocks were widely used before the invention of quartz and atomic clocks.
