Item needed while performing The Gravedigger of Drefia Quest. You can pick it up only once (I meant three pieces in the quest, but you bring only once), so if you want it as a decorative item you won't finish the quest. After the quest, you certainly can't collect them again. You can buy it at the market.
it seems to me that this item couldn't be started again. just like in oramond quest you can only take out one glooth farnina. after lehula's answer I have to add it to my statement because I'm not sure if anything has changed. cool as if someone checked it.