Return to Answer

As suggested in the comments, "what does superonic ice look like" in terms of its "natural" (reflected/transmitted) color is diffucult to access because the phase seems to exist only at high temperatures where its radiant "heat" would glow yellow/white. While the "natural" color cancstill be measured with the proper experimental setup (eg using a tunable chopped laser with a photdiode and lock-in amplifier(, samples amenable to such a setup are not readily available. If we were to compress water at a "non-glowing" temperature, even several hundred degrees Celsius, then at about 60 GPa or more we would see not superionic ice but Ice X. Ice X is a macromolecular phase in which the hydrogen and oxygen atoms are held by delocalized but fixed bonds.

Ice X might thus be considered as (fully) frozen superionic ice. It has cubic crystals, but information related to color/absorption spectra seems limited to infrared wavelengths. Chemistry LibreTexts reports:

Ice-ten looks identical as seen from the x-, y- or z-direction. Using a first-principles DFT code, ideal crystals of ice X have been shown to have a Raman peak at 998 cm$^{−1}$ and two infrared absorption peaks at 450 cm$^{−1}$ and 1507 cm$^{−1}$ [1].

(Visible light would be 12500-25000 cm$^{−1}$.)

Cited Reference

1. L. Jiang, S.-K. Yao, K. Zhang, Z.-R. Wang, H.-W. Luo, X.-L. Zhu , Y. Gu and P. Zhang, "Exotic spectra and lattice vibrations of ice X using the DFT method", Molecules, 23 (2018) 2780.

As suggested in the comments, "what does superionic ice look like" in terms of its "natural" (reflected/transmitted) color is difficult to access because the phase seems to exist only at high temperatures where its radiant "heat" would glow yellow/white. While the "natural" color can still be measured with the proper experimental setup (eg. using a tunable chopped laser with a photodiode and lock-in amplifier  (samples amenable to such a setup are not readily available. If we were to compress water at a "non-glowing" temperature, even several hundred degrees Celsius, then at about 60 GPa or more we would see not superionic ice but Ice X. Ice X is a macromolecular phase in which the hydrogen and oxygen atoms are held by delocalized, but fixed bonds.

Ice X might thus be considered as (fully) frozen superionic ice. It has cubic crystals, but information related to color/absorption spectra seems limited to infrared wavelengths. Chemistry LibreTexts reports:

Ice-ten looks identical as seen from the x-, y- or z-direction. Using a first-principles DFT code, ideal crystals of ice X have been shown to have a Raman peak at 998 cm$^{−1}$ and two infrared absorption peaks at 450 cm$^{−1}$ and 1507 cm$^{−1}$ [1].

(Visible light would be 12500-25000 cm$^{−1}$.)

Cited Reference

1. L. Jiang, S.-K. Yao, K. Zhang, Z.-R. Wang, H.-W. Luo, X.-L. Zhu , Y. Gu and P. Zhang, "Exotic spectra and lattice vibrations of ice X using the DFT method", Molecules, 23 (2018) 2780.

As suggested in the comments, "what does superonic ice look like" in terms of its "natural" (reflected/transmitted) color is not experimentally accessible because the phase seems to exist only at high temperatures where its radiant "heat" would glow yellow/white. If we were to compress water isothermally at too low a temperature, including several hundred degrees Celsius, then at about 60 GPa or more we would see not superionic ice but Ice X, a macromolecular phase in which the hydrogen and oxygen atoms are held by delocalized but fixed bonds.

Ice X might thus be considered as (fully) frozen superionic ice. It has cubic crystals, but information related to color/absorption spectra seems limited to infrared wavelengths. Chemistry LibreTexts reports:

Ice-ten looks identical as seen from the x-, y- or z-direction. Using a first-principles DFT code, ideal crystals of ice X have been shown to have a Raman peak at 998 cm$^{−1}$ and two infrared absorption peaks at 450 cm$^{−1}$ and 1507 cm$^{−1}$ [1].

(Visible light would be 12500-25000 cm$^{−1}$.)

Cited Reference

1. L. Jiang, S.-K. Yao, K. Zhang, Z.-R. Wang, H.-W. Luo, X.-L. Zhu , Y. Gu and P. Zhang, "Exotic spectra and lattice vibrations of ice X using the DFT method", Molecules, 23 (2018) 2780.

As suggested in the comments, "what does superonic ice look like" in terms of its "natural" (reflected/transmitted) color is diffucult to access because the phase seems to exist only at high temperatures where its radiant "heat" would glow yellow/white. While the "natural" color cancstill be measured with the proper experimental setup (eg using a tunable chopped laser with a photdiode and lock-in amplifier(, samples amenable to such a setup are not readily available. If we were to compress water at a "non-glowing" temperature, even several hundred degrees Celsius, then at about 60 GPa or more we would see not superionic ice but Ice X. Ice X is a macromolecular phase in which the hydrogen and oxygen atoms are held by delocalized but fixed bonds.

Ice X might thus be considered as (fully) frozen superionic ice. It has cubic crystals, but information related to color/absorption spectra seems limited to infrared wavelengths. Chemistry LibreTexts reports:

Ice-ten looks identical as seen from the x-, y- or z-direction. Using a first-principles DFT code, ideal crystals of ice X have been shown to have a Raman peak at 998 cm$^{−1}$ and two infrared absorption peaks at 450 cm$^{−1}$ and 1507 cm$^{−1}$ [1].

(Visible light would be 12500-25000 cm$^{−1}$.)

Cited Reference

1. L. Jiang, S.-K. Yao, K. Zhang, Z.-R. Wang, H.-W. Luo, X.-L. Zhu , Y. Gu and P. Zhang, "Exotic spectra and lattice vibrations of ice X using the DFT method", Molecules, 23 (2018) 2780.

As suggested in the comments, "what does superonic ice look like" in terms of its "natural" (reflected/transmitted) color is not experimentally accessible because the phase seems to exist only at high temperatures where its radiant "heat" would glow yellow/white. If we were to compress water isothermally at too low a temperature, including several hundred degrees Celsius, then at about 60 GPa or more we would see not superionic ice but Ice X, a macromolecular phase in which the hydrogen and oxygen atoms are held by delocalized but fixed bonds.

Ice X might thus be considered as (fully) frozen superionic ice. It has cubic crystals, but information related to color/absorption spectra seems limited to infrared wavelengths. Chemistry LibreTexts reports:

Ice-ten looks identical as seen from the x-, y- or z-direction. Using a first-principles DFT code, ideal crystals of ice X have been shown to have a Raman peak at 998 cm$^{−1}$ and two infrared absorption peaks at 450 cm$^{−1}$ and 1507 cm$^{−1}$ [1].

(Visible light would be 12500-25000 cm$^{−1}$.)

Cited Reference

1. L. Jiang, S.-K. Yao, K. Zhang, Z.-R. Wang, H.-W. Luo, X.-L. Zhu , Y. Gu and P. Zhang, "Exotic spectra and lattice vibrations of ice X using the DFT method", Molecules, 23 (2018) 2780.

As suggested in the comments, "what does superonic ice look like" in terms of its "natural" (reflected/transmitted) color is not experimentally accessible because the phase seems to exist only at high temperatures where its radiant "heat" would glow yellow/white. If we were to compress water isothermally at too low a temperature, including several hundred degrees Celsius, then at about 60 GPa or more we would see not superionic ice but Ice X, a macromolecular phase in which the hydrogen and oxygen atoms are held by delocalized but fixed bonds.

Ice X might thus be considered as (fully) frozen superionic ice. It has cubic crystals, but information related to color/absorption spectra seems limited to infrared wavelengths. Chemistry LibreTexts reports:

Ice-ten looks identical as seen from the x-, y- or z-direction. Using a first-principles DFT code, ideal crystals of ice X have been shown to have a Raman peak at 998 cm$^{−1}$ and two infrared absorption peaks at 450 cm$^{−1}$ and 1507 cm$^{−1}$ [1].

(Visible light would be 12500-25000 cm$^{−1}$.)

Cited Reference

1. L. Jiang, S.-K. Yao, K. Zhang, Z.-R. Wang, H.-W. Luo, X.-L. Zhu , Y. Gu and P. Zhang, "Exotic spectra and lattice vibrations of ice X using the DFT method", Molecules, 23 (2018) 2780.