A sorcerer turned the girls into stone to protect them. Alas, he was killed in the crossfire, and noone else could turn the girls back into their human form. So they stand till this day!
There's another version, where it was their DAD who turned them into stone, but that's another story ;)'
Awed by our beautiful world,
P.S. Guess what! The kids emailed to say that a kind man at the Opal store gave Mel a boulder opal! How's that for some ol' time Christmas spirit? :) It's kind strangers like these who will really make their holiday a trip to remember. To experience the kindness of strangers is like no other experience.
For somehow, not only at Christmas, but all the long year through, The joy that you give to others is the joy that comes back to you.