The popularity of crystal skulls is increasing as a preferred form for both collectors and practitioners. Usually carved from a single piece of stone, skulls can be hand or machine carved and are works of art and craftsmanship. Some skulls are carved to mimic the human skull, while others are carved with a head shape that can only be described as alien.
Metaphysical practitioners believe that carved skulls can be a port of call for spirit guides or alien beings. Said to inhabit the skulls, these entities can act on the user's behalf. In addition, crystal skulls can be used for meditation and the creation of energy fields; skulls are able to absorb and amplify energies and information.