Here are the gemological instruments:
A carat scale

a lamp adjusted to a dark-field to see up close quickly

a refractometer to measure light density

a polariscope to determine the crystalline nature of the material

(Isotropic or Anisotropic)

a Chelsea filter to determine the presence of chromium

a dichroscope to observe the pleochroism of anisotropic materials.

a spectroscope to observe the chemical elements making up the stone using the visible light spectrum.