Ge′ode

,

GE'ODE

, [Gr. earth.] In mineralogy, a round or roundish lump of agate or other mineral, or a mere incrustation. Its interior is sometimes empty, and in this case the sides of its cavity are lined with crystals, as in agate balls. Sometimes it contains a solid movable nucleus; and sometimes it is filled with an earthy matter different from the envelop.