Is your tea on ice, or is your tea ice?

Here's another one that people screw up all the time. In fact, product labels even screw it up sometimes. Check it out:

I'm having a nice glass of ice tea.

Here's where the problem comes in. What are you saying? Are you saying your tea is ice, or do you mean that your tea is on ice? I'm going to bet it's the second one. "Ice tea" would imply that the tea is actually made of ice. It's just like ice cube (a cube made of ice) or ice queen (a queen made of ice...metaphorically).