The Silt Block is a block found everywhere in the world below cavern level. Just like the Sand Block, it is affected by gravity, and will cause suffocation damage if dropped on the player. It is the only block that can "cover" Lava when dropped into lava pits. Be careful with silt and cobwebs since cobwebs can support the weight of silt, which will drop if the cobweb is destroyed (eg. by passing through it) and can cause suffocation damage to the player.