Spar crystals cover much of the walls in some sections of the cave. Typically they are a dull brown color like in this room. Large pieces of the spar coating have broken off on the right, exposing the limestone bedrock underneath.
<a href="//commons.wikimedia.org/wiki/User:Dave_Bunnell" title="User:Dave Bunnell">Dave Bunnell</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>