There is also a similar effort[1] to collect data on refractive index curves (against wavelength) for various materials, under CC0 (not CC-BY-SA, which seems a

There is also a similar effort[1] to collect data on refractive index curves (against wavelength) for various materials, under CC0 (not CC-BY-SA, which seems a bit ridiculous for objective physical properties). That’s much less immediately useful for rendering, though. [1] https://refractiveindex.info/ https://refractiveindex.info/