Volcano Survival

Well, another challenge map... somewhat like my Marooned one... but with a giant caaaaaaaaaaaaave and only one island. Without much further ado, the rules and goals-

Rules-
You MAY break/place blocks.
You MAY NOT use mods/inventory editors/map editors/anything else that gives an advantage
Play on Easy... or Medium/Hard if you're daring.... but probably Easy.
If you die, you fail, thus you restart and try again from the beginning

Goals-
Find the diamond block in the cavern
The cavern is located under the volcano
That's all.... so in case you couldn't tell, finding the diamond block is REALLY FRICKING HARD