u/prdycool

I'm trying to start a garden in my backyard, but everywhere I dig, I'm running into this! It's an interesting blue/gray color surrounded by red clay. Hitting it with something sharp chips it pretty easily and some of the smaller pieces you can crumble in your hand. First pic is in the ground, second is a freshly washed chunk with a small chip. Wondering how deep it might go and if it's worth trying to dig up or through. There's at least a solid 2' x 3' piece where I'm digging now.