Placing an amethyst under your pillow is supposed to help you sleep well. Unless it's one of those big, pointy ones, in which case you're likely to spend all night going "Ow!"
Amethysts are also supposed to ward off anxieties, nightmares and oversleeping. A small tumbled stone should work fine if you cleanse and charge it first.
Dorothy Morrison had a spell in 'Everyday Tarot Magic' that used the four of swords tarot card. I've used the same card to help charge sleep related items for sleep spells.
All that being said, hot milk with a little cinnamon works as well as any spell I've used
wow, that one's new to me, i might put some cinnamon in a milk.

