Advice on cleaning a rock.

[Jamastiene]

I lost my old petrified rock when we moved. I used it as a nice looking coaster that fit my home's decor. I recently found another rock that is flat enough to work as a new coaster and look nice.

I have one problem though. Other than rinsing it off, I am not sure how to keep it from leaving gritty bits of debris on the table. I know I am going to need to do more than rinse it off and glue some felt on the bottom.

Does anyone know of any tricks to laminate/lacquer/seal a rock to keep the little crumbly bits from ruining my tabletop? Even advice on how to clean it better than just rinsing it would help.

Thanks.

[LiberalEsto]

1. What about some stick-on cork?

I think pieces of corkboard with stickum on the back can be found in craft stores. Or just get some plain corkboard and glue it on.

[Viva_La_Revolution]

2. some kinds of rock, like sandstone will just continue to fall apart

especially if you're using it as a coaster and it's getting wet a lot. Water is the most destructive force of erosion.
You can try sealing it with a penetrating sealer, or you can look for a different kind of rock like dark marble or granite.

[mopinko]

3. clean it with muriatic acid.

but i would check out a tile store for some 4 x 4 polished tiles. most places will let you buy just a few pieces.
granite fabricators often cut scrap into small tiles. some also give away scrap.
teflon glides are the new felt.

[Adsos Letter]

4. I used a spray can of Deft clear laquer

I have a pretty good sized chunk of petrified wood that I put about 5 good coats of Deft on. it isn't super crumbly but it holds together nicely, and gives it a deep glossy coating. Deft aerosol is very quick drying.