Blue ice (glacial)

In glaciers, the pressure causes the air bubbles to be squeezed out, increasing the density of the created ice.

A large piece of compressed ice, or a glacier, similarly appears blue.

[1] So, water owes its intrinsic blueness (as seen after > 3 meters of penetration) to selective absorption in the red part of its visible spectrum.

Within hours these air filled fissures cloud the surface making the ice appear white.

[2] Blue ice is exposed in areas of the Antarctic where there is no net addition or subtraction of snow.