Quartz Sandstone Small 320×318 Medium 640×635 Large 1024×1016 Download TIFF Original 2418×2400 | (890.9 KB) Description Thin section of quartz sandstone shown under the microscope. The original rounded quartz grains are surrounded by new quartz, forming quartzite. Keywords geology, quartz, sand, sandstone Galleries Rocks Source: Amadeus W. Grabau A Textbook of Geology (Boston: D.C. Heath & Co., 1920) 455