Shattered glass!

I came up with this idea when creeper exploded a good chunk of my house, demolishing several windows nearby. The idea is rather simple: every glass block, upon breaking, should have a small probability to drop a glass shard. You can craft 9 glass shards into a 1 shattered glass block (which may be craftable into a shattered glass panel as the normal glass, but they will give 12 panels instead of 16 as normal glass). This block will also drop shards, but with even less probability. And 1 shattered glass block could be smelted into normal one. I think that's a balanced idea to make glass a bit less expensive on early stages but keep its fragility