It is water, not tile.

Here is the builder's website with better views.
Click on each picture to view the next.

http://www.distinguishedpools.com/portfolio.htm

Here are some other of their pools.

Simply magnificent!

Thanks for the question..In this case one edge of the pool is lower, water is taken from the basin below (I've attached a picture so you can see) then returned to the pool raising the level, it then gently flows over the lowered edge creating the effect that you see.

Breathtakingly beautiful.

Thank you!

@linsal2000 and Distinguished Pools - I think in the subject photo it looks like a slightly submerged hot tub area on the left side of the picture near the infinity edge? Is this what's throwing you off linsal2000 or is it the retractable pool cover? P.S. cool pool

Ingenuous!!

Ok thanks, I hope this helps @linsal2000. It also looks like maybe another level in the pool as well as the spa, like seat height 12-15" below the surface before it drops off the the deepest. Nice wide shelf in the pool for lounging and it looks like it may wrap around the long side of the pool to make it easier to step out. Nice detail.