Recognize a common noun when you see one. Nouns name people, places, and things. Every noun can further be classified as common or proper. A common noun names general items. Go into the kitchen.
A sandstone with at least 25 percent feldspar is called arkose. A sandstone made of volcanic particles is called tuff. The cement in sandstone is usually one of three materials: silica (chemically the same as quartz), calcium carbonate or iron oxide.
The carbonate rocks make up 10 to 15% of sedimentary rocks. They largely consist of two types of rocks. Limestones which are composed mostly of calcite (CaCO 3) or high Mg calcite [(Ca,Mg)CO 3 ], and.any limestones (carbonate rocks in general) show characteristics similar to those of clastic sediments, like sandstones. Sandstones are composed of sand grains, a mud or clay matrix, and a crystalline cement produced during diagenesis.