Quartz is a power stone that harmonizes and balances. It enhances energy and thoughts, and purifies the spiritual, mental, and physical. It is also a powerfully protective stone, bringing the purified energy in. Historically this crystal has been used to counter black magic, to perform diagnostic healing, and to communicate with spirits and other worlds. Clear quartz, as opposed to colored quartz, is associated with the crown chakra, but also works well on all chakras.