An unforgettable friend

A tortoise owned its legs and head befriended with a shiny diamond.
The diamond shone in the night but remained a rock in the day.
The tortoise turned into the wave when the diamond was given to the dolphin.
In the day,he was the wave,but,he was the tortoise in the night.
I loved the tortoise in the wave.
However,the diamond met him and materialistic came.
Maybe,this ending will let him bury in my own sea without wave!