So the Philosopher's Stone lets you break the Law of Equivalent Trade. The Law itself is an invention of the show, and as far as I can tell so is this exception. But other aspects of the Stone are drawn from historical alchemy.
There's the famous 'converting lead to gold' aspect--we went over that in Zerotime.
There's the 'healing all wounds' aspect--we went over that with Marco.
There's the immortality aspect. We haven't seen that.
Except now comes Dante, reassuring the boys: don't worry your heads about what your silly sensei told you about how the Law of Equivalent Trade doesn't apply to life! Just frolic in the garden! Also, do not speak of the Philosopher's Stone.
Except that unless I'm misinterpreting the Engrishy translation, it's rather heavily implied that Greed is Dante's creation. But Greed is hundreds of years old. On the other hand...Dante's got a great fucking hunk of red stone clasping her cape shut. Subtle.