Its prized possessions are the haunting Volto Santo ( Holy Face ) , a wooden crucifix said to have been carved by Nicodemus and possessing miraculous powers ; and the graceful white marble tomb of Ilaria del Carretto Guinigi by master Sienese sculptor Jacopo de lla Quercia ( 1408 ) in the former sacristy .
A wooden crucifix is its prized possession .