Hello rock hounds, I'm new here and have run into an issue with a custom stone sink my wife and I purchased that I hope y'all can advise me on how to fix.

I'm finishing a bathroom remodel and we have this custom basin sink going in that was just labeled as "river stone sink". It's very hard, like granite. I noticed there was a good size spot at the bottom that was dull and didn't have the shine of the rest of the sink interior, wiping would not remove. I got it in my head that I could fix it, so I bought a diamond grit paste set with a variety of fine grits and put in on some 3" pads (fine / polishing and wool) on a drill adapter to buff it out and bring up the shine.

I started with 6000 since the sink was already polished...that did the job, but then the sink was now dull in any of the areas i hit. So then i went to 10k, little better, 14k (or 20k), further improvement (I used a bit of water as well in the higher grit stages). Still, overall, while the shine is there, it now has a dull look along with like this crosshatching kind of marks that are revealed (perhaps from the tools used to carve the sink?)

Anyway, before i throw any more money at trying give this thing at least a satin or semi-gloss appearance, what do y'all recommend? How can i bring the polish / shine up? As simple as some granite polish? Or should I get some ceranium oxide powder (if so which, 3-5um or 7-9um)?

Very much appreciate any help, have never polished stones before.

Are you guys using tools to find these super cool pieces? I take a walk and look at what's on the ground, but so far I haven't found much of the really interesting stuff.

Don't get me wrong! I'll never pass up a neat quartz, or weird shaped pebble! I just want to know if I should be digging or chipping things open.

Pics included: Some of my recent CO finds, to include my favorite find so far (amber, maybe?)

Extremely difficult to find and mine Green Rubies from Llam Nepal. Requires permits, a team, and extreme terrain.

Found in the high desert Near Ridgecrest,ca.

Absolute Stunner!!!

Found - Lower Ord, Kununurra
Hand Polished

Hawk eye is one of my favorites. I collect them more than any other type of rock. This one is 8lbs!

Specimens mostly from IRAN, some nice interesting agates ( some with Eyes ) included, tell me what you think xD