The word "fabled" bothers me. I think this is referring to the Garden of Eden where fruits were like jewels made by God. "Fable" usually means fictious. Am I wrong here??
I don't think he is referring to the Garden of Eden at all. There are many fairy tales from many nations that refer to trees having jewel-like, or jewel-encrusted fruit, or fruits made of precious metals, usually gold.Look on gutenberg.org for the fairy tale books of Andrew Lang (Blue Fairy book, Brown Fairy Book, etc)
Those berries look delicious. Maybe I should have been a bird?