Science / Geology / Sandstone: A detrital sedimentary rock composed of grains from 1/16 to 2 millimeters in diameter, dominated in most sandstones by quartz, feldspar, and rock fragments, bound together by a cement of silica, carbonate, or other minerals or a matrix of clay minerals.

Quartzose Sandstone

Science / Geology / Quartzose Sandstone: (1) A quartz arenite. (2) A clean quartz sandstone, less pure than a quartz arenite, that may contain a moderate amount of other detrital minerals and/or calcite cement. MORE


Science / Chemistry / Abrasive: A very hard, brittle, heat-resistant substance that is used to grind the edges or rough surfaces of an object. boron carbide, diamond, and corundum are abrasives. MORE


Science / Chemistry / Oxygen: Element 8, atomic weight 15.9994, a colorless, odorless gas that makes up about 1/5 of the earth's atmosphere and (in combined form) 8/9ths of earth's oceans and almost half of the earth's crust. The MORE


Science / Geology / Arkose: A sandstone that contains at least 25% feldspar. Easily recognized because the feldspar grains are typically pink and angular in shape. MORE

Tar Sand

Science / Geology / Tar Sand: A sandstone containing the densest asphaltic components of petroleum - the end-product of evaporation of volatile components or of some thickening process. MORE

Quartz Arenite

Science / Geology / Quartz Arenite: A sandstone containing very little except pure quartz grains and cement. MORE