... Steps toward interstellar silicate mineralogy. ... Astron. ... Optical constants: . ... Deternimation of optical constants was made in two ways: (i) measurements of reflectance of the polished samples (0.19 - 500 micron) with following Kramers-Kronig analysis in 8 - 80 micron region and Lorentz oscillator fit outside the region; (ii) measurements of transmittance of the "raw" samples (with accounting for the reflected and scattered light contribution) in visual ( 100 micron). ... Related paper(s): ....