Sand occurs naturally and is composed of fine rock material and mineral particles. Its composition is variable depending on the source.
It is defined by size, being finer than gravel and coarser than silt. Sand is a great natural landscaping material and different types of sand are used for different reasons.
Playground sand, for instance, is (obviously) good for sandboxes, but also volleyball pits and beach themed landscapes. On the other hand, mortar sand can be used to place between pavers to create a decorative patio.