Sand

Sand is a block naturally found on coasts and deserts. Sand has a very low blast resistance.

Red Sand is a variation of sand that can be found in mesas. Red sand acts similar to sand, the only differences being color.

Obtaining
Sand can be broken using any tool, but a shovel is the fastest.

Natural generation
Sand generates naturally in many biomes of the Overworld, notably deserts, beaches, and rivers, generally in four-block-deep layers supported by stone and sandstone. Red sand generates naturally in mesa biomes and variants.

Usage
Sand, if there is no block below it, will fall until it lands on the next available block. When sand is being affected by gravity and falling, it exhibits a smooth falling animation.

If falling sand lands on a mob or the player and covers their head, it will suffocate them until they destroy the block, move out or die. If falling sand lands in the space occupied by a non-solid block, (such as torches, slabs, rails, or redstone), it will drop and turn into a sand item. If it falls onto a cobweb it will slowly fall until it has gone through it completely, or until it touches the ground, at which point it will turn into a resource block.

Sand can be placed on a non-solid block without falling.

Construction
Sand can be used in the construction of airlocks and the creation of mob suffocation traps. Being affected by gravity, it can be quickly and easily removed from ground level.

Farms
Sand and red sand can be used for farming cactus and sugar canes.

Falling sand
The FallingSand entity is able to take any texture of any block. By altering the BlockID and using the command, the player is able to create a falling block of another texture.

Data values
Sand has the ID name  and is further defined by its block data. Sand also has a block state which is expected to replace the functionality of block data in a future version.

Trivia

 * If a block of sand has snow on it and is made to fall, the snow is destroyed and will not drop snowballs.
 * Because falling sand is considered an entity it can be launched in a TNT cannon, similar to an ignited piece of TNT.
 * Sand will fall at the same rate when submerged in water as it will when in air.
 * If a player is standing on a stack of sand or gravel, and the stack falls on a non-solid block, the player will fall fast enough to take damage or even die.
 * Sand will fall through torches without breaking if there is air below the torch.
 * Sand and gravel take about 0.45 seconds to fall one meter.