Fig. 2.

Imaginary index of refraction k(λ) for crystalline forsterite Mg₂SiO₄ from this work (solid black line), compared to olivine with ~10% Fe content (gray solid line ≡ San Carlos olivine from Zeidler et al., 2011; dotted and dashed lines ≡ Fo90 gemstone in differing thicknesses; gray dashed line ≡ Fo90 meteoritic olivine). ForFo90 spectrum, noisy data regions dueto sample thickness vs. wavelength were cut at 2.1–2.5 and 4.5–5.0 µ m. For Fo90 ***Inline equation*** spectrum, noisy regions were removed at 2.5–3.0 and 4.4–5.0 µ m. Behavior in the Fo90 data near 1 µ m is at the limit of the VIS-NIR detector range and is therefore less certain.