I have found 14 diamonds in my underwater mine tunnel. I think the best way to use it in the next update is (Im not sure if this is true or not. I heard about how diamond tools will be added along with gold and iron tools.) making an diamond pickaxe, diamond sword, and diamond axe. 8 diamonds was my first vein, so that'll clear that up. Not sure about the other diamonds. But like I said, not sure if diamond tools are in the next update, just a rumor.
How many diamonds have you found on your survival map?