BeginnerExploration
How to find the End portal (stronghold) in Minecraft
Mining Infested Stone Bricks releases Silverfish, so expect a few.
Tested 26.3

The Infested Stone Bricks is disguised as Stone Bricks. An infested block hides a Silverfish that bursts out when the block is broken. All infested blocks work the same; the Infested Stone page explains them.
It is mined with a pickaxe and drops Stone Bricks.
This item has no crafting recipe.
Mining Infested Stone Bricks releases Silverfish, so expect a few.
It is a block that hides a silverfish, found in strongholds and mountains.
The fastest tool is the pickaxe.