translation.en: These are quartz crystals and feldspar, so most sand in the world on the mainland is made of quartz crystal and feldspar. It's the erosion of granite rock.
translation.zh: 这些是石英晶体和长石 也就是说地球大陆上大多数的沙 都是石英晶体和长石构成的 是花岗岩被侵蚀后的产物