I explained it partly in your other topic but I'll add some stuff to this reply.
Tia wrote:
no, destorying a weapon will only be caused if a wep fails to + at +5 or higher, it will either
The chance of destroying an item only exists when you try for +6 or higher without immortal (a blue stat) on your item.
1. Do nothing (not 100% sure)Yes the alchemy (stone) can succeed but not change the amount of str added.
2. Add some STR (success) It can succeed and either add str or take some str away (so with str 2 you can go to either str 1 or str 3/4/5/6).
3. Take away STR(fail) When it fails nothing happens. It's basically a waste of a stone, might as wel dropped it on the ground or something.
Then there is a chance of assimilating other stats (both white and blue stats). This assimilation can either be negative or positive, where the negative part is obviously changing the stat to something lower and positive changes the stat to something higher. It is possible to get two assimilations with one succesful stone. I am not sure if it's possible to have a useless assimilation (with that I mean changing the stat to what it already was like in point 1).