The Gevey Agate Field

Gevey agate field is located in 20 km southwest Toorbat-e-Jam little city, about 150 km Southeast Mashhad in northwest Iran. This agate field is situated in a limited outcrop of a volcanic sequence which composed mainly of andesite, trachyandesite, basalt and ignemberite lava and associated tuffs. This sequence which formed eminences of west Gevey village is Paleocene to lower Eocene in age, based on GSI surveying report. 

The economical importance of area is due to a little hydrothermally vein type mine of barite which is in operation now. Indices of agate, jasper and bentonite mineralizations found beside this mine later. Loose nodules of agate and geodes scattered on the surface by weathering. Most of nodules are “frozen” geodes, but good quality agates are not rare! Agates are white-gray in color. Fracturing related to weathering is fatal feature mostly. Geodes are filled with clear quartz and rarely pale amethyst crystals.  Presence of barite mineralization beside agates, limited vein jaspers  and bentonitization of tuff layers strengthen the theory of relation between genesis of agates and post volcanic hydrothermal activities.    

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Nodular agate with collapsed structure 60x43 mm