Destroying horcruxes by Avada Kedavra?

[zwarte_kat_1]

No: HPFGUIDX 134413

Does anyone have any thoughts on how to destroy an horcrux? 
It looks like it's only the part of the soul that is targeted,
which may cause some damage to the object in which it was concealed,
but does not destroy it: In the case of the ring, there seems to have
been only a crack down the middle of the stone and the diary was
damaged through the insertion of the Basilisk's fang, but not
destroyed.

How does one destroy a piece of someone's soul?
The part of Voldemort's soul inside the diary has been destroyed
by a deadly poison. The same poison nearly killed Harry. So, in this
case, what would have been deadly to a human was also effective in
destroying part of a soul.
I'm wondering if spells that can kill a person, could also
destroy an horcrux? 
What would have happened if Harry had cast Avada Kedavra at the diary?
Would that curse also have destroyed the horcrux?

zwarte_kat_1