Watching carefully to make sure no one and no critter was following him, he made his way inside. As a zhuji cultivator, his eyes were fairly sharper than before and he could see more clearer in darkness. As his eyes adjusted to the darkness, Ju Feng saw a dark narrow passage with various runic inscriptions, in front of him. He touched the walls of the dark passage and inspected it more closely.
"Obsidian shadow diamond."
Ju Feng muttered to himself. Although it was one of the hardest rock stones in the universe and extremely precious, its true value lied in its ability to contain defensive runes. Obsidian shadow diamond was one of the two known types of rock stones that could take the Total-Fortress runic inscriptions without dissipating. The other being the emerald-cloud stone. Extremely rich cultivators used it to build safe rooms containing their treasure vaults.