The shape of Shiva Linghams represent the male aspect of creation; the marking represent the female aspect. The total energetic effect of the stone is one of union and the activation of the kundalini energy that rises up the spine, activating the chakras and bringing enlightenment. They are emblems of inner-transformation, breaking up patterns of self-limiting habits and beliefs, clearing the way for rebirth. They stimulate the body's energetic systems, strengthening and balancing the entire body.
Simmons/Ahsian - "The Book of Stones"