Some Mineralogical and Gemological Properties of Silicified Wood Species in Western Anatolia

Abstract

The silicified wood samples identified in Western Anatolia are located in the Late Miocene-Pliocene aged Çokköy Formation in Tavşanlı (Kütahya) and its surroundings, in Osmancalı (Manisa) and its vicinity in the Early (?)-Middle Miocene aged Foça Tuff and in Banaz (Uşak) around in the Middle-Late Miocene aged Yeniköy Formation within the terrestrial sediments. The formation of woods petrified by the silicification mechanism is associated with the sedimentation of clastic sediments formed simultaneously with the Neogene period volcanic activities in the region. In the mineralogical-petrographic examinations on three oriented thin sections, including transverse, radial and tangential, chalcedony polymorphs of silica and less quartz and opal were detected in silicified wood samples. Mineralogical interpretations were also supported by X-Ray Diffractometry (XRD) analysis. As a result of paleobotanical definitions made with thin sections in the botanical microscope; Taxodioxylon Hartig 1848 (Swamp cypress), Pinuxylon Gothan 1906 (Pine), Pterocaroxylon Müll.-Stoll et Mädel 1960 (Walnut), Quercoxylon (Kräusel 1939) Gros 1988 (evergreen oak), Glyptostroboxylon Conwentz 1884 (Swamp cypress) fossil wood species were identified. According to these findings, a warmer and more humid climate prevails than today, cypress forests on the edges of swamps and streams, and pine and evergreen oak forests on the slopes were determined. Within the scope of gemological examinations of silicified wood samples, samples which are rich in color/pattern were selected, polished by giving cabochon forms, then mounted with silver. A small amount of facet cutting studies were carried out from unpatterned and monochromatic samples. Silicified wood samples, which have high values in terms of hardness, exhibit an unstable character due to the weak zones they contain and do not show the desired performance in terms of pattern/color.