This includes our physical bodies, which are akin to force fields with energy ever flowing through them. We are literal conductors of energy.
Crystals are tools that augment the flow of energy.
This applies not only to desirable energy, however, but to all energy, both positive and negative. Through conscious use of crystals as tools, we can enhance anything we undertake. Quartz crystals have electro-magnetic properties, hence their use in a lot of electrical devices. Crystals are often used in energy healing to augment the healing process. Crystals worn on the body either as jewelry or in one's pocket can magnify peace, awareness, vitality, or any other desired feeling.