Mineralogical Studies on Some Selected Semi-Precious Stones from Northeast Jordan

Abstract

A semi-precious stone is known as a gem or gemstone (also a jewel, a gem, a precious stone), which is a portion of mineral in refined and cut form that could be used to create a jewelry or other embellishments. A gem also can be defined as any mineral that is highly prized for its beauty, durability, and rarity, is used for personal adornment and has been enhanced in some manner by altering its shape usually by cutting and polishing. Semi-precious stones occurred as xenolithes are widespread in Jordan within different source of rocks. High grade of copper as malachite and chrysocolla and plancheite is suitable for gemstone manufacture found in Finan area. High purity of garnet can be found in metamorphic rocks in Wadi Araba area, whereas xenoliths of pyroxene, olivine and spinel-perioditite and garnet are wide spread in basalt and pyroclastic materials in northeast Jordan. The studied semi-precious stones are part of the Miocene alkali basaltic rocks that covered the northeastern part of Jordan within Harrat Al-Shaam Basaltic Super Group Plateau concentrated mainly in volcanic centers and volcaniclastic materials of Aritian, Hassan , Ufiyahim and Bishriyya formations. Some of these xenoliths and xenocrysts can be considered as semi-precious stones. This study is fo cused on characterization of petrography, mineralogy and geochemistry of these semi-precious stones like olivine, pyroxene and garnet xenoliths that have been collected from selected areas in northeast Jordan. The samples were analyzed by polarizing microscope, X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) and Scanning Electron Microscope (SEM). Cutting and polishing tests have shown that some of the studied xenoliths are suitable for manufacturing attractively colored gemstones and could be considered as semi-precious stones. The geological chances for the discovery of some hundreds of tons of th ese gemstone-raw materials are considered to be good in volcaniclastic materials that are associated within different volcanic centers at northeast Jordan.