Sand is composed of grains of rock, the size ranging from 0.06mm to 2.0mm. These particles are mostly quartz, although there are other minerals such as clays and irons mixed in. In contrast to Building Sand which is a fine, uniform sand. Sharp sand or grit sand is a rough, graded sand with a higher percentage of larger grain sizes. It's uses include making plaster and mortar, screeding floors, laying paving, top dressing lawns and on greenhouse capillary benches.
Sharp sand is the ideal sand for laying block paving upon. It also makes an excellent "stiff" mortar mix for laying all types of patio paving on. When using sharp sand to lay paving a good idea would be to lay them on a bed of 50mm sharp sand with a cement ratio of 1:6. Mix it dry and this will give your patio rock solid foundations. Sharp sand is also commonly used in the garden in seed composts and propagating benches, as it's coarse open structure allows moisture movement from area to area. This also makes it ideal for adding openness, air and making soil freer draining in heavy areas of the garden.