We added in Glass in this most recent update. Glass is mostly inert, but can be formed by mixing Sand and Magma, and also can be broken by nearby explosions, turning it back into more Sand.
Unfortunately, somewhere along the way, we lost our version of the code containing the removable top and bottoms and managed to break the eraser. We fixed the eraser, but as still working to fix the top and bottom. Thanks for bearing with us!