when u break a block and it gives u nothing instead it should give cobble stone and u should be able to smelt it and make stone there should also be something you can craft with cobbelstone and the stone that u hopefully add after this comment
I had this exact idea as well! I want to change things a bit: instead of having a "random" chance, I wanna add clusters of materials, e.g. a "coal cluster" or "diamond cluster" similar to other popular crafting games. Hitting a cluster will take a bit longer to mine and while mining you'll be able to see "what's inside". Mining a "non-cluster" will be much quicker and indeed it gives you something called "stone" you can then use to craft "buildings" (like the furnace) or walls. Walls will be interesting to block a path once there are enemies that might kill you. (stay tuned for that!)