When Alex and Conner try to gather the magical items they need to make the Wishing Spell work, one "ingredient" is a jewel from Snow White's glass coffin. "Glittering jewels whose value increased after preserving the false deceased." When Alex and Conner try to find Snow White's glass coffin at her palace, Snow White tells them she gave it back to the dwarfs and it's in the dwarf mines. When they take a few, there are already other jewels missing from the coffin. Apart from being an ingredient for the spell, it does not say if the jewels have any other magical qualities.