Because of the Chemical Composition as well as Vibration, crystals have the most amazing healing properties - please refer to my section: Crystals to see the healing properties of each crystal I put out.
Life is all about energy and vibration and every single living thing vibrates at a different frequency. Each Crystal Vibrates on a different frequency which the body needs in able to balance and heal our energy fields within the body.
Please refer to my article on the Energy fields in the "Blog" Section of my website where it explains more about the energy fields, what happens when they are out of balance, or even when they are over stimulated. Crystals together with Reiki gives for pretty powerful healing as Reiki energy amplifies the healing abilities in crystals making the power packed little healers.
Do contact me if you need any more information on Crystals and their healing abilities.