Quite rightly, this body of water is called the Crystal Lake, the huge body of water just about as far up north on Rubii as you can get. Fed by an underground hot spring, it gradually drains into the Aaoi River. Oddly enough, the minerals that collects around the Crystal Lake from the rich waters turns to a chilly mist when it hits the fresh water of the river. The whole thing is rather odd, but loved much by Rubii’s inhabitance, as it is known to cure ailments of the body and mind, and it collects some valuable creatures deep in its crystalline depths.