leptyniteMin.|ˈlɛptɪnaɪt| Also leptinite. [app.f.Gr. λεπτύν-ειν (see next) + -ite.] The same as granulite. 18..Dana (Worc.), Leptynite.1879Rutley Stud. Rocks xii. 211 Granulite (Weiss-stein or leptinite) is also composed of felspar and quartz, the felspar being orthoclase.