Shiva lingams are named after the Hindu God Shiva, and they resonate deeply with the energies of the Earth, yet they also have carry strong energies of Water, Wind and Fire. In fact the Fire energies of these stones is so strong that they are capable of activating Kundalini energies and charging the entire chakra system. For those who feel they need a boost of vitality and prana energies, meditating or sleeping with Shiva lingam is highly recommended.
Esoteric legends suggest that there is a field of invisible knowledge in which the stored psychic energy of human ritual and belief may reside. When one makes a connection to some portion of this field, one can tap into the energy of all the past consciousness that has contributed to it. Thus when one works with a sacred object like the Shiva Lingam, one can receive the benefit of the efforts of all those who have used such stones in spiritual persuits throughout history. This is especially true because these stones are composed primarily of microscopic Quartz. Through crystal resonance, any Shiva Lingam can connect to all others through out the world, in all places and times. Through this power, Shiva Lingam can be emblems of inner tranformation.
Source: The pocket book of source by Robert Simmons.