Yes that is a Pebble Tile. Black River Rock.

Are there any issues with Efflorescense or Freeze/Thaw concerns with this type of tile? Also is it flagstone n the top edge of the spillover wall? I love this look!

No issues with Freeze as long as you set it with no air gaps behind it, it must be solid. The Coping Stones are Thermal Finish Blue Stone - They were all 18" widths by 3' long. Thank you for your comments, we are very proud of this job.

I'm sorry, yes Efflorescent's can be controlled using a good sequestering agent in the pool water and keeping your pH - Alkalinity - and Calcium balanced. This particular pool is sanitized using Salt Water Chlorination and we treat it with "Jack's Magic Magenta Stuff" which is very effective, but there are other good ones on the market as well.

What type of mortar do you use to set the tile and what type of material is the backing of the tile made of? Sorry for all the questions - I'm renovating my infinity edge pool and looking for appropriate materials for the wall edge. Thanks!

Its no problem - For something like this we wouldn't suggest a premix, we use a Portland Cement Type I/II mixture with fine mason's sand and water - 3 parts sand - 1 part cement, If you want to add a cup of an acrylic bonding agent then that would be fine too. Depending on the size job you are doing will depend on what you want to mix it in, only mix enough so as you can use it within 30-40 minutes at a time. Mix it to a consistency that will stand to a 3" - 4" slump.