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

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 Camkoy 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 Camkoy garnets. The garnet/biotite geothermometry gives an average temperature of 526.9 +/- 29.8 degrees 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 Camkoy region might have a remarkable economic value, showed bright, transparent and pure crystals ever be found.