All 3 bedrock faces visible (with stone for comparison)
Not to be confused with Solid blocks
Bedrock or Adminium, also known unofficially as Admin Blocks, Adminite, and several other variations, is the unbreakable stone found at each extent of the map except the ceiling. It occurs both naturally, and can be created by admins and ops (with the command /solid). The natural variant cannot be destroyed, nor built on, but 'admin stone' can be destroyed by other ops.
For a larger profile picture, see here.
Bedrock that is exposed on the bottom of the map will often turn into lava when the game is closed and reopened in Indev.
The bottom of maps in Alpha Mode have an uneven layer of Bedrock. It is not possible to mine the Bedrock, but there are often holes in the Bedrock which allow you to fall through the bottom of the map.