Abstract: Agates in the study area, located around the town of Almus in Tokat province, are found in the form ofnodules along an approximately E-W trending fault within the volcanogenic sandstones of the Almus formation.The Upper Cretaceous aged Artova ophiolite complex, represented by metabasic ,and ultrabasic rocks on top of thePaleozoic aged Tokat metamorphics forming the basis of the study area, stands at the tectonic boundary, ,and theHaydaroğlu formation, which includes the Middle Eocene aged volcanogenic units, cuts ,and covers these older units.Sedimentary rocks such as sandstone, conglomerate ,and marine limestone containing volcanic materials belongingto older units, as well as the Lower Miocene aged Almus formation, which contains the agates, also unconformablyoverlie all units.Almus region agates contain on average 93.4%SiO2, 3.59%Fe2O3, 0.03%MgO, 0.72%CaO, 793 ppm Cr2O3,11.98 ppm Ni, 13.4 ppm Cu, 4.69 ppm Pb, ,and 35.4 ppm Zn. They are associated with the ophiolite complex, whileCu, Pb ,and Zn are associated with the early stages of volcanism. The high Fe2O3 content in agates is associatedwith hematite and goethite which were transported in agates before SiO2 emplacement. The CaO in the agate isthe product of the last phase of the solution forming the agate, and MgO is associated with the presence of dolomite. Field observations and geochemical evaluations of agates show that agates are epigenetically emplaced as aresult of the circulation of SiO2, which is the main component due to hydrothermal activities that occurred after therock formation of the Haydaroğlu formation, within the volcanogenic sandstones.