Making rocks somewhat shiny

Hi. Geologist here. So I have a bunch of rocks here and I plan on starting making resin dioramas and stuff to sell and I want to use a lot of the rocks that I've collected. I have two tumblers so I've been using them and I am trying not to spend a lot of money so I have been using other rocks sand and metal beads to tumble. It's been working pretty good the rocks or jagged but the edges are smooth and I think that Dell work really well for background of fairy houses and such. My question is that they're not shiny. I don't expect them to be really really shiny but a little shine would be nice. Now I have read about this and I guess there's three stages that you have to go through and they each take like a week and they each take this grit to do and I don't have the money to spend on all that. What I've been doing has been working out effectively enough they're not rounded but the edges are smooth and they look pretty. I would just like to shine them up a bit so is it a thing where I can just get a really fine grit to shine them at this stage?