noun 다운로드 🔗공유 장석 Any of a large group of rock-forming minerals that, together, make up about 60% of the earth's outer crust. The feldspars are all aluminum silicates of the alkali metals sodium, potassium, calcium and barium. Feldspars are the principal constituents of igneous and plutonic rocks. Examples : "Many granite countertops are made up of quartz, mica, and feldspars. " 많은 화강암 조리대는 석영, 운모, 그리고 장석으로 구성되어 있습니다. geology mineral material science AI와 채팅어휘 게임독해 연습