The Hallow



The Hallow is a Hardmode surface biome. It has an easily recognizable cyan-colored grass, multicolored trees, and a huge rainbow in the background. It is the only biome where you'll find Unicorns, Pixies and Gastropods. The Underground Hallow biome can be found directly under a naturally-generated Hallow biome.

Hallow does not exist in a newly-generated world. Instead, it is generated along with a large Underground Hallow biome when the Wall of Flesh is defeated the first time. The Hallow can also be artificially created by planting Hallowed Seeds in dirt, using Holy Water or Blue Solution, or placing Pearlstone and Pearlsand blocks.

The Hallow is the only environment through which the Corruption and Crimson cannot spread at all. Consequently, its role is very important in hardmode, where the corruption becomes nearly unstoppable. The Dryad will tell the player the percentage of Hallow and Corruption/Crimson in the world. Neither the Hallow, Corruption nor Crimson can spread through the Underworld, and the Hallow cannot spread through mud biomes like Jungles or Glowing Mushroom biomes.

Although activating hardmode requires the player to have good equipment, the Hallow is a challenging biome, especially at night, since it is home to powerful mobs. Do not be fooled by the cute and childish scenery.

Hardmode
As soon as Wall of Flesh is defeated, a section of Hallow spawns. This stripe goes from the Underworld to the surface, converting stone, sand and grass in its path into pearlstone, pearlsand and hallowed grass, respectively. This does include floating islands that happen to be in the path of this stripe. The Hallow's stripe can intersect with the Corruption's chasms as well as Floating Islands.

Hallow spreads in a manner very similar to corruption:
 * Hallowed grass can spread to Dirt Blocks or grass in the Surface Layer with at least one side exposed to air.
 * Stone Blocks can be converted to Pearlstone Blocks.
 * Sand Blocks can be converted to Pearlsand Blocks.
 * Ice Blocks can be converted to Pink Ice Blocks.
 * Pearlstone and pearlsand can spread through any depth, not just the Surface Layer.
 * Blocks that are up to three squares away from an existing hallowed block can be converted, even if unhallowable blocks are in the way.

There are also a few differences in the way that the Hallow spreads:
 * The Hallow can spread through its vines (but can not "go up" through regular vines).
 * The Hallow does not uproot sunflowers, but can still spread beneath them.
 * Pearlstone does not seem to create hallowed grass as fast as ebonstone creates corrupt grass.
 * The Hallow cannot convert mud or jungle grass. This means the Hallow can be completely superseded by the Jungle causing no blocks to become Hallow.

Pre-hardmode
Hallow does not normally exist before the world enters hardmode, but can be created with Hallowed Seeds, Holy Water, or the Blue Solution (for use with the Clentaminator) imported from another world. If it is created, it will only spread the same way as pre-hardmode Corruption: slowly, on the surface, and only through dirt and grass. This means you can safely use other hallowed blocks without creating a biome and converting regular blocks in pre-hardmode worlds. It still prevents the Corruption from spreading. Furthermore, Hallow-specific mobs will not appear, since they were only designed for hardmode.

Hallowed Desert


When the Hallow spreads through desert, it becomes Hallowed Desert. It is very similar to the Hallow: the music theme is the same, the mobs are the same (except for the Light Mummy), and the background is slightly different.

The sand is replaced by pearlsand. Although their color is different, cacti still drop cactus when cut, and waterleaves are also able to grow.