Chiastolite is a special form of Andalusite. It is an aluminium silicate mineral. Usually Andalusite forms as transparent crystals which can be cut and faceted, but it can also form in upright pillars. These may have carbon inclusions within, which form in a cross shape perpendicular to the crystals axis of growth. These are revealed when the crystal is sliced across its axis, and the stone is then described as Chiastolite.
Cleansing and grounding, Chiastolite is an excellent form of protection and (as you might suppose from its X / + shape) a profound connection to the Divine Self and to the energies of the Christ. At the same time its grounding properties enable it to channel and earth High frequencies into the human energy body and the planet.