It amplifies good energy and thought as well as the effect of other crystals. Clear Quartz wards off negative energy of all kinds. Some call it the universal stone and master healer as it white contains all the colors in the color spectrum.
Wands are used to focus energy on a certain point where you need the energy to flow
This can be used for cleansing your crystals as well. Just placed it near the crystal that you wish to cleanse.