Crystal healers use a variety of expressions to describe a crystal for a specific purpose such as healing or meditation. Some healers consider "tuning" to be the same as "dedicating". Others refer to the tuning process as "energizing" or "programming" their crystals.
Tuning your crystal is analogous to preparing to listen to a radio station. When you cleanse and dedicate your crystals you are "switching them on". When you tune then, you are selecting the desired wavelength. tuning a crystal involves having the intention to use the crystal for a particular purpose.
Tune each crystal individually making it easier to remember its particular purpose, e.g. one for meditation, one for healing.
It is important to tune directly after cleansing and dedicating.
Remain in a relaxed alert state and hold your crystal in one hand and place the other over it. Vizualize an energy connection between you and the crystal e.g. a ray of white light. Decide on the crystal's purpose and say "I intend this crystal to be an effective tool for...... e.g. healing, meditation"