Search for diamonds

Well...today,i was finding diamonds.
I mined a stairway...and didnt found anything.Just some coal,gravel,dirt,and mainly stone.
But look!In the corner!

Its...a...redstone!
I am suprised i finally found it.
So.I got to the layer 0 of bedrock...and started counting.
1...2...3...4...5...and no more bedrock.
6...7...8...9...10...lava level.Too good i have a water bucket!
11...12...13...14...15...lets start mining here.
I am mining...zomg hax more redstone!
Okay,lets make some room here.

Before i made workbench and a chest...i found this.
Lapis Lazuli!
But i am not finding this.
But...'mines'
Right.Lets make this deeper,and pick a spot for shafts.
Okay,workbench and chest placed.
Lets mine first shaft...one redstone found.
Second...2 lapis lazuli ores found.

Third...a lot of redstone and coal!
Forth...many iron and coal.
Okay...lets connect the shafts.
After 5 minutes...connected,but no diamonds or gold.
I need a better luck...or better MCEdit.