The peach tree was transformed into Eden's apple tree in the Judeo-Christian tradition, and its ability to bestow immortality, into the "knowledge of good and evil," but it's the same tree, which early proto-Christian mystics (the Essenes? -- I recall reading that the Dead Sea Scrolls seem to prove Jesus was a member) had adopted and adapted to their own interpretation. Like its later apple tree offshot, the peach tree of immortality is guarded by gods and is off limits to mere mortals -- with a few notable historic exceptions. A mortal can get a peach off that tree as a crowning gift of cultivation, once in a blue moon -- the peaches ripen only once in ten thousand years -- or get it by accident, as two unremarkable boys once did simply because they got exceptionally lucky. They met a guy who had worked on his gong for ten thousand years to get to that tree, and as he was carrying his peaches in a very nice mood, he gave one to the boys. This is one of my favorite legends because it phases in the probabilistic nature of taoist cosmology which, apart from things written in the stars and things left to free will, has room for things left to pure chance ("luck" in taoist astrology's terms, "good" or "bad" or even "dumb" in human terms). When the two boys ate the peach and immediately showed up at the palace of the Celestial Immortals, the Jade Emperor goes, who the hell are they? One of his assistant gods checks up on the boys in the book of destiny and, indeed, it predicts that around this day, two unremarkable boys chance upon an immortal who might, on a whim, give them one of the divine peaches and so they are destined to become Celestial Immortals. The Jade Emperor then shrugs his shoulders: you lucky bastards, no cultivation, no quest, no merits, not even any money to buy a peach, the old man just gave it to you? What has he been smoking? Now even I can't overrule the book of destiny, for even my own destiny is left to its chances, to an extent. OK then, make yourselves at home, you've got an eternity to idle away...
And that's how I chanced upon my peach sword too. The day I decided I needed it, I went to an antique store and it was just sitting there waiting for me, in a bucket full of antique canes and umbrellas and suchlike. I guess it was written in the book of destiny that I was supposed to get it the moment I wanted it.

Its handle is carved as one of those immortals' heads with the egg-shaped cranium; the ritual I follow calls for writing my own talismans on it, with special ink (which I also have to make myself), and then doing a few more things, depending on what I want to use it for.