Do you have a small sample that you can take with you to a waterline tile store, like NPT? Keep in mind the pebble color will look different at different depths (for example a shallow shelf much different than 6 foot deep) and different sunlight.

You can also search the Houzz pool photos. Put in "Pebble Sheen French Gray" in Photos. Then narrow to outdoor, pool using left navigation. 179 photos. First photo I pulled up had your sheen. So you could look at other water tiles used.
[Pebble Sheen French Gray[(https://www.houzz.com/photos/pools-and-spas-elements-landscape-traditional-pool-atlanta-phvw-vp~24360668)

www.poolenvironments.com Although we typically use a quartz finish. Grey is our "go to" color. It looks beautiful paired with just about anything. I would focus on the overall look you are trying to achieve in your backyard and go from there. Here is one example, but you can visit our profile to see many more choices.