Reinforced Stone is explosion resistant, and is a good choice for building a Creeper/TNT safe bunker, or for housing a nuclear reactor. It can be mined with a Diamond Pickaxe, Diamond Drill, Dark Matter Pickaxe, Red Matter Pickaxe or Red Morning Star.
It is the third most resistant material after bedrock and the End Portal Frame with a blast resistance of 150. (In Vanilla Minecraft Obsidian has a blast resistance of 6,000; however, Obsidian was dialed back by Industrial Craft, lowering its blast resistance to 40). Reinforced Stone can withstand a nuclear explosion when a wall of it is built 3 blocks thick. It also is entirely impervious to equivalent exchange's Catalytic Lens, Hyperkinetic Lens, and Destruction Catalyst but does not block it from destroying blocks behind or within it.