1. Refractometer: A refractometer is a device used to measure the refractive index of a gemstone. It is used to determine the gemstone’s optical properties, such as its clarity, color, and brilliance.

2. Spectrometer: A spectrometer is a device used to measure the spectral properties of a gemstone. It is used to determine the gemstone’s chemical composition, such as its elements and minerals.

3. Polariscope: A polariscope is a device used to measure the optical properties of a gemstone. It is used to determine the gemstone’s optical properties, such as its pleochroism, birefringence, and dispersion.

4. Ultraviolet Light: Ultraviolet light is a device used to measure the fluorescence of a gemstone. It is used to determine the gemstone’s fluorescence, such as its color and intensity.

5. Microscope: A microscope is a device used to measure the physical properties of a gemstone. It is used to determine the gemstone’s physical properties, such as its size, shape, and inclusions.