I have found a HUGE diamond, gold, and redstone cave and every time I mine each one it just destroys it with nothing in return. I am using my Iron Pickaxe, play on the lowest difficulty, and just recently bought the game. This is very confusing and fustrating for me. Is this a glitch in the game or am I doing something wrong?
In my experience, Mincraft: XBox 360 Edition can be a little glitchy about placing blocks, rendering lighting, and sometimes mining. But I haven't seen it this bad. Generally restarting Minecraft, or rebooting the XBox, will help the game perform better.
So, I would restart the XBox and try again. If this fails, I might try crafting a new iron pickaxe, but that's just a guess.