A professional who examines gemstones, such as jade, sapphires, and rubies, to evaluate their genuineness, quality, and value, utilizing knowledge of gems and market valuations. Responsibilities include:

• Examines gem surfaces and internal structure, using polariscope, refractometer, microscope, and other optical instruments, to differentiate between stones, identify rare specimens, or to detect flaws, defects, or peculiarities affecting gem values.
• Immerses stones in prescribed chemical solutions to determine specific gravities and key properties of gemstones or substitutes, which indicate physical characteristics of stone for gem identification, quality determination, and for appraisal.
• Grades stones for color, perfection, and quality of cut.
• Estimates wholesale and retail value of gems, following pricing guides, market fluctuations, and various economic changes that affect distribution of precious stones.
• May advise customers and others in use of gems to create attractive jewelry items.