Justin, thank you! I'm glad you like this look. These are 1 - 1.5" thick quartzite stones set on "sand" -- typically about 2" of bedding sand or decomposed granite fines, over 4" of compacted base rock (typically about 5/8" size), with decomposed granite between the stones. As long as the patio is contained with something like header board or metal edging, the d.g. helps lock them into place. In this case we didn't use edging, and you can see that some of the outside stones are actually starting to shift.

I hope this is helpful… good luck!

—John