Sand dollars have five points not six and they are not shellfish, they are sea urchins.
Sand dollars connect to folk lore in the following ways:
A variety of imaginative associations have been made by idle beachcombers who run across the bleached skeletons of dead sand dollars.
The tests are sometimes said to represent coins lost by mermaids or the people of Atlantis. Christian missionaries found symbolism in the fivefold radial pattern and dove-shaped internal structures.
“Aristotle’s lantern” has been discerned in the distinctive perforations of keyhole sand dollars.