What are the solutions to the riddles?

A word of Warning

These are not hints to help you solve the riddles.
They are the full solutions.

Hint: All about but can't be seen...

Hint: At the sound of me...

Hint: Bright as diamonds...

Hint: Each morning I appear...

Hint: Glittering points...

Hint: I am always hungry...

Hint: I am only useful...

Hint: I am seen in the water...

Hint: I go around in circles...

Hint: I drive men mad...

Hint: I turn around once...

Hint: If a man carried my burden...

Hint: If you break me...

Hint: Lighter than what...

Hint: Lovely and round...

Hint: My life can be measured in hours...

Hint: Three lives have I...

Hint: To unravel me...

Hint: Until I am measured...