Infested Block

Infested blocks are blocks disguised as stone, cobblestone, or any stone bricks variants, but spawn silverfish when broken in Survival or Adventure mode.

Natural generation
Infested stone bricks are occasionally found in strongholds and igloo basements in place of normal stone bricks. Infested mossy and chiseled stone bricks also spawn in igloos. Infested mossy and cracked stone bricks do not generate naturally within strongholds, with the latter within igloo basements.

Infested cobblestone is found in the rarely generated "fake secret end portal" room of woodland mansions.

Mineral veins
Infested stone can generate in the Overworld in the form of mineral veins. Infested stone attempts to generate 7 times per chunk in veins of size 9, from altitudes 0 to 64, within one of the following biomes, or within a chunk that is at least partially occupied by one of these biomes:



Post-generation
Are generated when a silverfish enters the respective normal block form. $$, letting a silverfish enter regular stone bricks turns them into infested stone instead of the infested stone bricks.

Breaking
When the block is broken, whether by a player or by an explosion, a silverfish spawns where it was broken. Infested blocks either break instantly or take longer to break than their normal stone counterparts, and take the same time regardless of the tool:

Usage
When mined, an infested block spawns a silverfish that immediately attacks the player. If the player attacks a silverfish directly with a sword, bow, or potion of Harming, or when a silverfish takes poison damage, nearby infested blocks break, spawning more aggressive silverfish. If the silverfish is killed in one hit, then nearby infested blocks do not break, and no silverfish spawn from them.

Identifying
Note blocks placed on infested blocks produce piano sounds, while those placed on non-infested stone, cobblestone, or stone bricks produce bass drum sounds.

$$, a player can distinguish infested from normal blocks by observing that an infested block takes longer to break when using a pickaxe than the stone it appears to be, but without pickaxe, it breaks faster.

Mining an infested block with Silk Touch drops its non-infested counterpart, and does not spawn the silverfish.

A silverfish does not spawn if the block is destroyed by the ender dragon.

$$, using the debug screen, a player can identify whether or not a block is infested.

When an infested block is destroyed by a player in Creative mode, a silverfish is not spawned.

ID
Java Edition:

Bedrock Edition:

Block data
In Bedrock Edition, monster eggs use the following data values:

Trivia

 * Despite silverfish being able to infest cobblestone, stone bricks and mossy stone bricks, they cannot infest mossy cobblestone.