Determination of spectroscopic features and gemstone potential of garnet crystals from the Çamköy region (Aydın - SW Turkey) using XRPD, XRF, Confocal Raman Spectroscopy, EPMA and gemological test methods

Abstract

ABSTRACT: The investigated garnet samples have reddish to purplish-brown colors and typical dodecahedron shapes. Their crystals usually show dull luster. These garnets have mainly almandine composition, namely Alm_0.64-0.71 Grs_0.16-0.22 Pyr_0.07-0.14 Sps_0.01-0.05. These results are supported by XRPD, CRS and EPMA measurements. The Çamköy garnets exhibit depletions in Large Ion Lithophile Element (Sr, K, Rb, Ba) and High Field Strength Element (Th, Ta, Nb, Ce, P, Zr, Hf, Ti, Y) on Chondrite and Continental Crust normalized multi-element diagrams. On the other hand, the intense to moderate enrichments in U, Mn, Co and Fe elements play an effective role in the formation of reddish to purplish-brown color in the Çamköy garnets. The garnet/biotite geothermometry gives an average temperature of 526.9 ± 29.8 °C at 5.5 kbar. All mineralogic, spectroscopic, geochemical and gemological data indicate that the euhedral garnet crystals with a slight star effect in the Çamköy region might have a remarkable economic value, showed bright, transparent and pure crystals ever be found.