Investigation of the usability of ultramafic rocks as gemstonesin the Mersin ophiolite

The Mersin ophiolite is one of the Cretaceous-aged massifs located on the southern slope of the Central Taurus Mountains, tectonically bounded to the east by the left lateral strike Ecemis fault, to the north by the Bolkardag metamorphic rocks, and it is covered to the south and to the west by Miocene carbonates. The Mersin ophiolite complex is an approximately 6-km thick oceanic crust section, contains from bottom to top metamorphic sole, harzburgites, ultramafic and mafic cumulates, basalts, and deep-sea sediments. The ultramafic rocks in the Mersin ophiolite are mainly represented by dünite, harzburgite and pyroxenite, weathering surfaces that are red-brown and brown-colored, and a fresh surface that is dark green-green and display weak or high serpentinization. These rocks present granular, mesh and poikilitic textures, have low CaO and Al2O3, high MgO, alkali and FeO contents. This study aims to investigate the suitability of ultramafic rocks (peridotites, pyroxenites and serpentinites) of the Mersin ophiolite as potential gemstones; and to determine their potential usage in the jewelry industry through processing gemstones identified by geological and mineralogical analyses. Samples taken from the region were cut into gemstones for use in jewelry by applying stone cutting stages, including cabochon and faceting cuts and were then made into jewelry by using various forms of different metals. The ultramafic rocks from the region can be considered usable as gemstones thanks to their properties such as easy cutting, good brightness, processability, light-dark green color and patterned appearance.