Lewis & Short

marmŏrārĭus, a, um, adj. [marmor], of or belonging to marble, marble. (postAug.): faber, Sen. Ep. 90, 15.
Subst.: mar-mŏrārĭus, i, m., a worker in marble, marble-mason, Vitr. 7, 6; Sen. Ep. 88, 15; 90, 13; Firm. Math. 8, 19.