حجر رملي - المعرفة
Sandstones fall into several major groups based on their mineralogy and texture.. quartz arenites are made up almost entirely of quartz grains, usually well sorted and rounded. These pure quartz sands result from extensive weathering that occurred before and during transport and removed everything but quartz, the most stable mineral.; وهو سهل في معالجته، واستخدامه ...