Petey, the whitish, long stuff is granite from the trash pile of a local granite fabricator. It was free, only required [a lot of] elbow grease and will outlast me and whoever ends up with my house.
In the past, I used my variable speed angle grinders to profile and polish the granite, but I lucked out and got a Flex polisher with all the water attachments already on it.
Not counting the 4x4 caps for for the doggy "swamp," I had about fifteen or so pieces to do. I butted the composite tops to the granite and caulked everything, so water invasion shouldn't be much of a problem.
All the composite was attached using table top clips that slipped into slots made with my biscuit machine. Everything feels solid. When the caulking between the composite and the vertical 2x's is done., it'll be even more solid.
Got the rest of the winter to decide how to hide the angled pieces.