There is no "special" type of sand needed for sandblasting. Any type of sand can be used as long as it is coarse and has a flat surface. The difference between regular sand and blasting sand is that the latter has been screened to remove any large or sharp particles which could damage the surfaces being blasted. Blasting sand is typically available from specialty suppliers who sell it for use in sandblasting operations. However, if you are unable to find a supplier in your area, ordinary construction sand can be used as a substitute. Just be sure to screen it yourself to remove any large or sharp particles before using it.
There is no special type of sand needed for sandblasting. Any type of sand will work. However, the smaller the grain size, the faster the blasting will take place. The difference between regular sand and blasting sand is that blasting sand is more rounded and less sharp, which means it won't cause as much damage to whatever it's being used on. Blasting sand can usually be found at a hardware store or a welding supply store.