quartz: 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
mineral: solid homogeneous inorganic substances occurring in nature having a definite chemical composition
phytolaccaceae: chiefly tropical herbaceous plants (including shrubs and trees) with racemose flowers: genera Phytolacca, Agdestis, Ercilla, Rivina, Trichostigma