I love ice, when I was in Antarctica many decades ago, I got to see a lot of ice. And the one thing that impressed me -because I love to talk about ice - is that it has a color.

There's something very magical about water and what happens to it when it freezes. I don't think there's anything else in the world, perhaps in our universe, that is quite like ice.

Mainly, of course, if you're not an ice climber, where you really need ice, for most people ice is a damn nuisance. And we just can't wait for it to all melt.And it's always a remarkable fact that it takes so long to melt because the temperature of the air can be well above the freezing point, and the ice is still solid there. So for most people, that's the experience.

I think the most remarkable thing about ice, in my opinion at least, is that it occurs in many, many, many different forms. Most solids occur in typically one or maybe two or three different forms, and ice has approximately 15 different crystal forms, as well as two forms that are called amorphous, which means without any shape at all.

H2O it's a complicated, three-dimensional, charged object. And one can pack these things in many different ways, a little like playing the child's game of jacks, where those complicated little objects can be thrown together in all different ways.

The principal reason it transforms is that water is a collection of molecules, H2O, every child learns that.And that bond has the property that as the bonds get stronger when you cool water, the ice expands.

Normally, you would not call ice a mineral.