The Ancient Riddle - what does JKR know?

[zgirnius]

No: HPFGUIDX 157374

Tonks:
> Finishing my Alchemy 101 studies I have discovered this interesting 
> point.  Apparently the stone can NOT be destroyed.  I wonder if JKR 
> knows this.  DD must have figured it out somewhere between book 1 
> and book 2.  But does Rowling know??

zgirnius:
I think Rowling may know this fact, I agree with your (snipped) 
evidence that she has some familiarity with alchemy. However, Rowling 
takes elements of familiar/real things out there and alters them to 
suit her own purposes in various ways. So she could be doing this here.