Why can't I mine diamond, gold ore, or redstone ore?
Normal blocks I can mine fine, but when it comes to diamond and gold ores, the block just gets "destroyed" (as in you can't pick it up). I'm playing on multiplayer with no spawning monsters.
A pick made of iron will mine all ores.
A stone pick will only mine coal, and iron; but will destroy gold, diamond, redstone and emerald without dropping the item.
The diamond pickaxe is the only pickaxe to get obsidian.
A wooden pickaxe will only mine coal, diorite, granite, and stone.
Ah, that makes sense. I just got back to playing this after a long hiatus and can't seem to remember anything lol.
What I do is use a cobblestone pickaxe for mining stone, and a diamond pickaxe for mining gold|diamond|redstone. Since I only use this diamond pickaxe for these rarer ores, it is lasting forever. It lasts *much* longer than an iron pickaxe.
You can guess which kind of axe you need by the time it takes to mine. If it takes longer than a few seconds, you need something better (the ranking is wood & gold < cobblestone < iron < diamond). The only exception is obsidian for which you need diamond and it still takes half a minute
@Denilson Sa, if you strip-mine 10-16 lvls above bedrock you can find diamond easily, allowing you to use the diamond pick on everything and just make a new one from all the diamond found.
To expand on Tobias Kienzler's comment: The Digging page on Minecraft Wiki now has info about the precise effects of tool and block on mining speed.