These are the sparkling turquoise tiles we're having on the back wall of the downstairs toilet. They're probably rather brighter than this - particularly when the lights are shining on them. It was just very difficult to get a good picture; my camera lens isn't wide enough.
The lights are now in - although they were done after I took these pictures. There is a sensor to detect movement, and the lights go on automatically. Without the doors on, the lights have been going on every time someone passes through the hallway, but it gives you a chance to re-admire the tiling every time, so it's not a nuisance.