Ice Blocks

Ice Blocks are a common block type found alongside Snow Blocks in the Snow and Ice biomes. They can be mined with a pickaxe or drill. Ice Blocks have low friction, causing a player walking over them to slide when stopping or changing directions. This effect can be mitigated by equipping Ice Skates or other accessories crafted from them.

Ice Blocks can be converted into three other variants via the spread of biomes: These will also spread their respective biomes.
 * Corruption spreads onto Ice to create Purple Ice Blocks
 * Crimson spreads onto Ice to create Red Ice Blocks
 * Hallow spreads onto Ice to create Pink Ice Blocks

Crafting
Note that only normal Ice Blocks can be used in most crafting. Pink, Purple and Red Ice Blocks cannot be used in conjunction with, nor as a substitute to, Ice Blocks, and as such must be converted beforehand if usage is desired. Pink, Purple and Red Ice Blocks can only be used in the crafting of Ice Torches and their respective Hallowed, Corrupt and Crimson Torches.

There is no way in the game to melt ice into water, nor to freeze water into ice.

Trivia

 * The Corruption, Hallow, and especially the Crimson variants bear functional resemblance to SCP-009 - Red Ice from the SCP Foundation Wikidot, which itself is a reference to Ice-Nine from the 1963 novel Cat's Cradle. All are solid forms of water that can self-replicate by contaminating adjacent ice.

History
Eisblöcke Blocs de glace 얼음 블록 冰雪块