Grandfathers Unfinished Stone Board

Hi all,

Not sure where else to reach out regarding this, hope some people have some insight.

I have an unfinished board made by my late grandfather. It is an alternating stone pattern made by stone from his fathers old job site. It seems to be cast in some sort of resin, but it’s not touched up at all.

I’d really like to finish up this board and make it a sort of family heirloom. I don’t have any experience in stone working, but my father might? Be able to handle the woodwork(he has been a trim carpenter for 30+ years)

I’m a broke college kid, so I don’t have an arm and leg to spend on repair, but I also don’t want to ruin it trying to repair it myself. Would love any help or thoughts from people who might know more.

I will try to post pictures below.

Ps. I’m nearby Madison WI if that helps with anything

Overhead Image of what I have

Are the tiles just glued together with the resin? If so, you could try to attach a slab of wood (5mm? / .4 inch) to its bottom to stabilize it. Then mayhaps one could sand the top until you get a smooth surface which then in return is suitable for a finish?