Abstract: Recently, the Gem Testing Laboratory of Jaipur from India has encountered three aventurine feldspar samples which have been primarily proved belonging to the potassium feldspar rather than the oligoclase (sunstone). The samples studied here appear to be sunstones as they readily display aventurescence.However, the physical, optical and chemical properties of the samples do not match to that of sunstone but to that of potassium feldspar.The overall features of the samples are consistent to those of orthoclase feldspar.