Mod Podge

I use this for all my rocks that I paint. It doubles as a glue and sealer. I also like the fact that it is water based it then comes off your hands easily.

Perfect matte finish

This dries to a perfect matte finish, there are so many uses for this product from sealing art projects to puzzles, decoupage and even re-adhering your book spines.
Very easy to apply, I use multiple thin coats and it only takes about 15 or so to dry each coat.
Very happy with the results.