Optical properties of calcite and gypsum in crystalline and powdered form in the infrared and far-infrared

The complex indices of refraction for crystalline gypsum and calcite were determined from reflectance measurements for both single crystals and pressed powder pellets. These optical constants were determined from a classical dispersive analysis (DA) of the reflectance data to facilitate comparisons between the crystal and powdered data. This study was done to show the usefulness and the limitations of using pressed pellets for determining the complex refractive index of materials unavailable in single crystals.