I personally think it is 12.
What is the best layer to mine for diamonds in Xbox 360 edition of minecraft?
korey 29.04.2015
Go all the way to bedrock then up 3.
Elijah 30.04.2015
I've had a lot of luck at layer 12 also. But any layer between 16 and 3 should be fine. But any time I go mining for Diamond, layer 12 is the one I head to first.
puffin57 30.04.2015