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Silica gemstones formation in Yamadag volcanites (Arguvan-Malatya) mineralogical, geochemical, gemological properties and economic importance  
Yazarlar
Dr. Öğr. Üyesi İlkay KAYDU AKBUDAK
Kırşehir Ahi Evran Üniversitesi
Doç. Dr. Zeynel BAŞIBÜYÜK
Kırşehir Ahi Evran Üniversitesi
Meltem Gurbuz
Ayten Oztufekci Onal
Fikret Isler
Özet
Yamadag Volcanics which is one of the examples of the Late Miocene volcanism in Eastern Anatolia covers large areas within the boundaries of Arguvan county of Malatya. The gemstones, subject of this research range from a few centimeters to about 30-40 cm in size and are formed in the cavities of the basalts beonging to Yamadag volcanics. These gemstones seem to have formed as veins extending in east-west direction and consist of opal (opal-CT) and chrysocolla. Opal formations have various colours such as white, brown, yellow and greenish, while chrysocolla formations are bluish-greenish in color. both opal and chrysocolla are of massive type and their fresh surfaces display waxy luster. Mineral paragenesis and formation conditions of gemstones and are determined by applying XRD, SEM, FT-IR techniques. ICP-MS technique is used for the determination of the geochemical compositions. The gemological characteristics are identified via cabochon and facet cut techniques by using diamond coating blade, sintered diamond abrasive discs and polishing machine. Opals are usually composed of tridymite minerals, also in some cases quartz and cristobalite minerals accompany the tridymite minerals. The EDX measurements reveal, enrichment of Fe and Al in opals, and of Cu in chrysocolla. The ICP-MS measurements, in chrysocollas reveal, enrichments in LIL elements such as Ba, Sr and in HFS elements such as U. Consequently, gemological studies show that the chrysocolla and opals in study area, which have waxy luster and massive structure, are suitable for utilization as a gemstone due to its color, hardness, durability, homogeneous distribution of color and processability.
Anahtar Kelimeler
Mineralogy-geochemistry, gemology, opal, chrysocolla, gemstone, Malatya
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY
Dergi ISSN 1300-1884
Dergi Grubu Q4
Makale Dili İngilizce
Basım Tarihi 1-2018
Cilt No 33
Sayı 1
Sayfalar 211 / 219
Doi Numarası 10.17341/gazimmfd.406793