Thank U Darling!
The pond is concrete, the island is concrete too. This picture is old, and it is from the time I was still building it...or beautifying it.
I put mosaic on top of the island made from broken tiles, which I cut with a grinder into squares...now it is finished...and I put also shade on top.
There is a river around a meter deep going to one side which is not seen.
I will soon post some pictures from the water fall and water feature I made DIY...