Pulverizer

A block similar to furnace but instead of smelting blocks you can pulverize stone to cobble, cobble to gravel, and gravel to sand using fuels like the furnace. This would allow for players to turn there excess stone/cobble or gravel into sand allowing for crafting of concrete powder, TNT, and glass. This also allows for players to turn stone/cobble into gravel for flint that allows for the ability to craft more arrows and flint and steel. 
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