"massive blocks of yellow sandstone"

Sandstone
Creative Commons Attribution Share AlikeSandstone - Credit: Ester Inbar
 Sandstone is a common sedimentary rock formed by the consolidation and compaction of sand and held together by a natural cement, such as silica, quartz, haematite and clay minerals. It can vary in colour from yellow or red to grey or brown. Sandstone is widely used either as a primary building material or as a facing stone, over other construction.