Amazingly, you can use regular old dirt as an inclusion in glass art. Well, recycled glass art, I don’t know about that fancy schmancy art glass stuff.
Easy enough. Dig out a little pile of dirt from your yard. Put it in a terra cotta saucer and run it through a firing cycle. This burns off all of the organic stuff, that stuff that will smoke and cause bubbles in your artwork.
Then, you add the dirt in between layers of glass. Fuse as usual, and voila! One small insider trick: if you use tiny pieces of glass to prop the layers apart as you fuse, the air will escape and securely trap your dirt.
I learned this cool trick when I had a client who collects dirt from her various travels. Turns out dirt is different colors from all over the planet…until you fire it. Then it’s pretty much the same. Luckily we discovered this early on and didn’t destroy her unusual keepsakes.