What is sand made of?
Sand is made of minerals and tiny pieces of rock that have come from the erosion and weathering of rocks. The composition of sand varies from place to place depending on the sources and conditions of the local rocks. The most common constituent of sand in inland continental settings (e.g. deserts) and non-tropical coastal settings (e.g. beaches), is silica (silicon dioxide SiO2), often in the form of quartz. Arkose is a sand or sandstone with a high content of feldspar (an Aluminum Silicate), usually derived from the weathering and erosion of nearby granite. Much of the fine white sand found in coral reef settings is ground-up coral (limestone) that has passed through the digestion system of the parrot fish. Some places have sands that contain magnetite, clays, chlorite, glauconite, or gypsum. Sands rich in magnetite are dark to black in color. The chlorite – glauconite bearing sands are typically a green color. The gypsum sand dunes of the White Sands National Monument in New Mexico a
