Also , the low index of refraction of calcite allows light to penetrate several millimeters into the stone before being scattered out , resulting in the characteristic `` waxy '' look which gives `` life '' to marble sculptures of the human body . Also , the low index of refraction of calcite allows light to penetrate several millimeters into the stone before being scattered out , resulting in the characteristic waxy look which gives `` life '' to marble sculptures of the human body .