Mason Sand

Mason sand is finely screened natural sand with small, smooth, uniform grains. The particles are washed clean of clay and silt, and the top size is usually under 1/8 inch. That fine texture is why bricklayers can spread it into thin mortar joints without fighting the trowel. It's the same reason you sweep it into the cracks between pavers instead of reaching for something coarser.

The name comes from ASTM C144, the spec masons use for mortar sand. That spec limits how much dust and oversize grit can be in the pile, so any load labeled mason sand should feel clean and easy to work with. White mason sand is the same material screened from a lighter-colored deposit, and it usually costs a bit more because those mines are less common. Prices tend to sit close to concrete sand at most yards.