Dictionary of Superstitions - David Pickering I haven't actually "read" this tome. I picked it up today at one of my libraries for a dollar and already I've learned something:

molucca bean A kind of bean or nut, sometimes worn as an amulet in the Western Isles of Scotland....When witchcraft is threatened the beans turn black, warning of misfortune or death. They are particularly credited with assisting women in childbirth and with preventing death by drowning....

I look forward to acquiring many more superstitions in the months ahead.