It's just a rock.

"However," the young cultivator said as he eyed the two ladies of the Misty-Cloud Sect. "I wonder if you two elder sisters could help us? We've been tasked with taking this sword artifact, but as you probably saw, we can't pull it out of that rock."

"I don't mind giving it a try. But why don't you just destroy the rock? Someone of your strength could do that easily." Zi Ya said as she made her way toward the sword hilt sticking out of the stone. 

"Others have tried, but it seems to have a protective formation that reflects all attacks." He explained just as Zi Ya was about to summon her strength to punch it and hopefully crack the rock in half. She gulped and changed her mind. Instead, she climbed on top of the rock and pulled on the hilt. It didn't budge.