Abalone shell is made up of microscopic calcium carbonate. Some applicators add the shell in the mixing process and that can lead to weak spots and scaling in the finish. Also there is no real need for the abalone to be in the finish below 18 inches. The deeper the water of the pool the less visible the shimmer of the abalone becomes. The abalone really comes to life on steps, sun benches and walls above 18 inches of water depth. The way to get the longest life out of the abalone shell is for the applicator to broadcast the shell over wet plaster prior to exposure. If the abalone shell is added to the mixer, less of the shell is likely to make it to the surface as well as possibly causing scaling problems in the future. Abalone shell can really enhance the look of your exposed aggregate pool finish.