Pebble finishes are an exposed aggregate pool finish.
The applicator takes premixed bags of small tumbled and polished pebbles and mixes them with white cement and sometimes a coloring agent. Towards the end of the application they lightly water wash the finish to expose the uppermost portion of the pebbles. The next day the applicator will come back and acid/pressure wash the finish to remove chalkiness and better expose the pebbles.
This is an awesome pool finish, I'm certain you'll love it.

See ya,
Kelly