ephesiteMin.|ˈɛfɪsaɪt| [f.ephes-us, near which it was found + -ite.] A pearly-white lamellar mineral, closely related to margarite. 1851Amer.Jrnl.Sc.Ser. ii. XI. 59 Ephesite [a new species].1873Proc.Amer.Phil.Soc. XIII. 387 Ephesite, a mineral of..lamellar structure..resembles white cyanite.