What are the four types of sand?

The four types of sand are commonly classified by grain size, composition, or use, and several systems use four categories. By geology and composition, the four main types are quartz sand which is the most common silica-based sand, feldspar sand which is slightly pink and less weather resistant, mica sand which is sparkly and flaky, and biogenic or calcareous sand made from crushed shells and coral found in tropical regions. By grain size under the Unified Soil Classification System, there are four sand sizes, very fine sand 0.05 to 0.1 millimeters, fine sand 0.1 to 0.25 millimeters, medium sand 0.25 to 0.5 millimeters, and coarse sand 0.5 to 2 millimeters. In construction, the four most used types are concrete sand for mixing concrete, masonry sand for mortar, fill sand or utility sand for leveling, and play sand which is washed and screened for children's sandboxes. Another popular four type breakdown for consumers is pit sand from pits, river sand from riverbeds, sea sand from beaches which is salty and not ideal for construction, and manufactured sand or M-sand made by crushing rocks. Each type has different properties and uses, so choosing the right sand matters for strength and safety.