Agate Geode Slice

Agate is a rock consisting primarily of cryptocrystalline silica, chiefly chalcedony, alternating with crystalline quartz.

Geode slices

agate geodes are geological secondary structures which occur in certain sedimentary and volcanic rocks. They are themselves of sedimentary origin and naturally made by chemical precipitation. Geodes are hollow, vaguely spheroid to oblate masses of mineral matter. It may include crystals.

It is form either by the filling of vesicles in volcanic to sub volcanic rocks by minerals deposited. From hydrothermal fluids or by the dissolution of igneous nodules or syngenetic concretions. And partial filling by the same or also other minerals. It is precipitated from diagenetic water, also groundwater or hydrothermal fluids.

agate geodes differ from vugs in form. Its form comes early, rounded. They structures within the surrounding rock. Geodes also differ from nodules. A nodule is a mass of mineral matter that has accreted around the nodule nucleus. Both structures had the minerals contained within, deposited from groundwater or also hydrothermal processes.