Silt Block

Silt Blocks were added in 1.1, and falls under the soils category, and like sand are subject to gravity. They deal damage to any player or mob they fall on.

Location
Below cavern level.

Uses
Silt can be used in the same way as sand, and can be used to fill lava pits. It can also be used to function in various traps, since it causes damage to whatever it falls onto.