Bed Rock is the layer right before Compressed Granite, indicating that the player is approaching the map's boundaries.
Its surface is rough, barely reflective and taupe colored. It's a tough material, requiring five hits from your Pickaxe before it breaks, and you will mine out a smaller area than other types of Common Rock.
Bed Rock and Compressed Granite cannot be drilled, it is assumed that the Driller's Reinforced Power Drills are not powerful enough to break it apart, while larger drills such as the one on the Drop Pod and Resupply Pod can. Glyphid Oppressors, Glyphid Dreadnoughts, and Glyphid Bulk Detonators can dig through Bed Rock. However, the Bulk Detonator's death explosion does not remove the material.