Silica is silicon dioxide, a compound of silicon which is found in sand, quartz, and flint, and which is used to make glass.
N-UNCOUNT
Silica is silicon dioxide, a compound of silicon which is found in sand, quartz, and flint, and which is used to make glass.
N-UNCOUNT
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012