Mineralogical, geochemical, and gemological characteristics of silicic gemstone in Aydıncık (Yozgat-Turkey)

Atomic and microstructural origin of banded colours in purple-blue variety of agate from Yozgat Province, Turkey

“…Table 1 summarises the average value of the concentrations of trace elements measured by LA-ICP-MS and collected in four different points on white and blue bands. The results are qualitatively in accordance with those reported by Başıbüyük (2018) from agate mined in the same region, albeit our concentration is one order of magnitude lower. It is interesting to note that the small but statistically significant variations between the white and blue areas concern only ions that do not cause significant colouration in quartz.…”

“…The 545 nm peak can shift up to 620 nm and, as a consequence, the same sample may appear coloured in purple, grey or yellowish only by changing the treatment temperature (Cheng and Guo 2020). Thus, the observed characteristics of the 570 nm peak in our sample is in agreement with Fe-related colour centres of amethysts and, notably, in some geodes from Yozgat Province this mineral has been found associated with agates (Başıbüyük 2018). Further experimental evidence about this interpretation can be found examining the absorption peak collected at low temperature (inset of Fig.…”

“…According to Hatipoğlu and Chamberlain (2009) and Hatipoğlu et al (2013), they include: Saricakaya (Eskisehir), the most relevant Turkish blue chalcedony deposit used since the Roman period, Kibriscik (Bolu), Bayat (Afyon), Aliaga and Bergama (Izmir), and Zile (Tokat). Recently, purpleblue agates coming from the Yozgat Province, which is located in the northeast part of central Anatolia, have come onto the gem market (Başıbüyük 2018). The agate samples from the Yozgat area can be found in the cavities of post-Lutetian alkaline andesites volcanic host rocks (Büyükonal 1985).…”

“…The agate samples from the Yozgat area can be found in the cavities of post-Lutetian alkaline andesites volcanic host rocks (Büyükonal 1985). The formation of this agate, accompanied by presence of amethyst, white quartz, and reddish brown amethyst (Başıbüyük 2018), occurred during secondary processes in volcanic rocks, which is the most common process of agate genesis (Götze et al 2001). In this work, we present a characterisation of agate from Yozgat Province, investigating both the bulk mineralogical composition by means of X-ray powder diffraction and the mineralogical phases' variations in correspondence of the differently coloured bands using confocal micro-Raman spectroscopy.…”

Cechy geologiczne, petrograficzne, mineralogiczne, geochemiczne i gemmologiczne rubinów z Malatyi

“…There are many mineralogical formation regions in Türkiye with gemological features of high quality and with precious stone features (Ethem 2007). Examples include Almus agates in Artvin (Başıbüyük et al 2023), Ch-chalcedony in north Anatolia (Başıbüyük et al 2020), chalcedony-amethyst formations in Yozgat (Başıbüyük, 2018;kaydu Akbudak et al 2018a), Opals in kütahya (Esenli et al 2001), in Ordu (Uz et al 2003) and various other parts of Türkiye (Esenli et al 2003;Esenli and Ekinci-şans, 2013). In these studies, the physical qualities of the gemstones in question were also determined.…”