Amethyst - Allows for a peaceful sleep as the amethyst radiation eases the passage from the physically conscious mind to the unconscious.

Citrine - It prevents nightmares and eliminates fears ensuring a good sleep. Citrine is also a good dream stimulator.

Rose Quartz - It can help release negativity and promote calm and well-being. It promotes a good and restful night's sleep.

Moonstone - Because of it's associations with the moon, the bringer of sleep, this stone can ensure restful sleep.

Crystals can be placed near the bed. There are many many articles on the web about how to cleanse and charge crystals, just google charging crystals or something like that.