Often thought of as one of the best "all round" crystals, amethyst is associated with calm, healing + balance. It's believed to support restful sleep, aiding in releasing or relieving overthinking and mental chatter. It's also considered useful to help overcome stress, anxious emotions, irritability or grief.
Amethyst is believed to be a protective crystal, and can be a good choice to meditate with, particularly when working towards breaking addictive or detrimental behaviour patterns. It's also believed to be helpful in strengthening ones intuition + mental clarity.