Mineralogical, petrological, and geochemical characteristics of Şenkaya Chrysoprase, Turkey
Özet
Şenkaya chrysoprase is a gemstone and can be found near the Turnalı village located in the west-northwest of Şenkaya (Erzurum)
county in the uplifted Kırdağ of Northeast Anatolia of Turkey. Chrysoprase only found in Şenkaya County and known with the same
name commercially in Turkey is a light-dark green and cryptocrystalline structure gemstone encountered in the Örükyayla Mélange.
Samples were collected from the field for defining mineralogical-petrographical, XRD, XRF, ICP-MS, optical cathodoluminescence
microscopy (OCLM), FTIR-Raman and stable isotopic properties of Şenkaya chrysoprase. According to mineralogical and petrographic
examination, Şenkaya chrysoprase has generally heterogeneous color distribution in macroscale and has 5 Mohs mineral hardness.
Microquartz filling (10%–15%) was seen in the microexamination with serpentine as main component with partly massive opal type
silica. The XRF analyses indicate that many samples had high SiO2
values (91.45–94.38 wt%). As a result of trace elements, rare earth
elements, Au-Pt group analyses using ICP-MS, Ni (167–387 ppm) and Co (12.57–74.78 ppm) values are quite remarkable. In the OCLM
studies, few metallic minerals which could produce CL and could spread CL in different colors due to some trace activator elements were
observed. Oxygen isotopic (δ18OV-SMOW) values obtained from three chrysoprase samples are 24.8‰, 27.7‰ and 30.63‰, respectively
and mean formation temperature is 96–99 o
C.
