Eugene in the winter always has one strong week of ice and snow, which I love. I spend a lot of time reading about ice growth, deformation, and dissolution as it is analogous to the mineral my dissertation is focused on - quartz. Both are hexagonal and remarkably similar - and ice has a much more extensive published literature behind it than quartz does. Often times, if a quartz question comes up that hasn't been investigated by petrologists the answer can be found in the ice literature ~90% of the time. Ice trumps quartz in the variety of structures it makes at the surface of the Earth, though.
Many ice formations are the result of intricate growth-dissolution cycling. Add fluid flowing downhill and you're bound to get a bunch of neat things (like flow lines scouring the underside of asymmetric ice dendrites nucleated at puddle boundaries and growing inward).
Sometimes you can see bubbles pushed against the ice.
Vermicular dissolution in cloudy ice.
Lobate ice dendrites.
Icicles (not from Eugene but from Sunriver, OR)
Why are the bubbles concentrated in the center?
I'm perpetually enthralled and confused by how perfectly ice preserves the equilibrium form (spheres) of bubbles.