Prehnite is said to connect the solar plexus with the heart - helping ones will be guided by the heart rather than the mind, this brings warmth and clarity into our actions. Prehnite is also said to help ground one in the energy of the earth. Wearing prehnite is said to help cool anger and ground excessive nervous energy. Prehnite is an excellent stone to bring on any spiritual retreat as it will help connect with the heart and ground with the earth. Black tourmaline is said to help keep the aura balanced and offer grounding to those who hold it. It is considered a powerful shield against bad vibes or psychic interference. Black tourmaline is said to clear feelings of unworthiness and help free one from attachments.