It really, really is.
They seem to be spiraling gradually down into the heart of the mountain. At one point they emerge from the end of a corridor into a huge natural-looking cave, lit by veins of luminous crystal in the walls and floor and ceiling, with an underground river flowing through it; in the very center of the cave, the river splits around a massive crystal formation, a cluster of seven perfectly clear six-sided pillars that reflect and amplify the light of the smaller, cloudier, brightly-glowing crystal spars around them.
Zekanare clears the broad path of the water in a single casual hop and keeps walking, though he slows down a little to let her get a good look at the place.