4/10/2021 · Argentina has long played an important role in the continent's history. Following three centuries of Spanish colonization, Argentina declared independence in 1816, and Argentine nationalists were instrumental in revolutionary movements elsewhere, a fact that prompted 20thcentury writer Jorge Luis Borges to observe, "South America's independence .
When quartz sands are crushed they produce particles with sharp, angular edges that are sometimes used to make sandpaper for smoothing wood. Some quartz sand is found in the form of sandstone. Sandstone is a sedimentary, rocklike material formed under pressure and composed of sand particles held together by a cementing material such as calcium carbonate.