White Chalcedony brings the mind, body, and spirit into alignment and harmony.  It is a protective stone that absorbs negative vibrations and energy, allowing it to dissipate to prevent onward transmission.  It will also protect you from negative people.
Chalcedony is also a creative stone that opens the mind to new ideas. It enhances receptivity to new solutions to existing problems and promotes new ways of thinking.  It inspires us to use our imaginations and insights when we wish to start new projects and helps the brain to assimilate new information quickly. It is said to facilitate learning a new language, improve memory, and enhance listening and speaking skills.
To cleanse and charge your crystal: the best way to cleanse your White Chalcedony is to run it under warm water.  
To charge, leave it inside an Amethyst geode or next to a crystal of Amethyst, or by the light of the moon.