枕块

to use clay for a pillow (during mourning period)

pillow / to pillow / to rest one's head on (Taiwan pr. [zhen4] for this sense)

lump (of earth) / chunk / piece / classifier for pieces of cloth, cake, soap etc / (coll.) classifier for money and currency units

bed of straw and pillow of clay (idiom) / the correct etiquette for a filial son during the mourning period