I love art, sculptures, and nature. Therefore, I have a tendency to choose things that are natural and go well together. Rock is beautiful and makes a great addition to any setting if you know how to use it and present it correctly. I build a lava rock, bamboo, and natural wood bathroom at my home. It is beautiful, but you need to take into consideration your environment and how hard it is to keep them looking like this.
If you live in a country with a lot of rainfall and humidity this, in my opinion, is not a wonderful choice. The rocks will turn green with moss or mold on them and you'll need to keep cleaning them to keep them looking beautiful. I end up cleaning my rocks in my bathroom every few months to keep them looking nice and the green mold or moss off of them.
Anything you chose for a decoration needs care and takes time to keep it looking good. Even if you use wood in your surrounding it needs to be kept up. The elements around you will soon weather anything if you don't keep adding a new coat of varnish or washing the mold or moss off the rocks.