Reinforced Deepslate is an indestructible block found exclusively in ancient cities. It has an extremely high hardness of 55, is immune to explosions, and cannot be obtained in Survival mode, even with Silk Touch. It is not affected by pistons and cannot be broken by the Wither or the Ender Dragon.

It has no associated tool, meaning it takes the same amount of time to mine regardless of the tool used. Breaking Reinforced Deepslate takes 82.5 seconds and drops nothing. A total of 56 Reinforced Deepslate blocks generate in the center of each ancient city, forming a frame-like structure.