 Built in 1440 , the Madrasa Gawhariyya contains the tomb of Gawhar al @-@ Qanaqba 'i , a Sudanese eunuch who became treasurer to the sultan . The floor of the madrasa is marble , the walls lined with cupboards , decoratively inlaid with ebony , ivory , and nacre . The tomb chamber is covered by small arabesque dome . 
