unique and different.....

If I have a tomato plant that bears a crop of red tomatoes except for one, which is bright blue, I think that I could honestly say that that would be "unique". No tomato, however, is exactly the same as its brother, whatever the colour or shape or size, so it can be asserted that all tomatoes are different from each other. Notice that 'uniqueness' is a quality that, although it involves comparison, essentially stands alone. 'Difference', on the other hand, always implies a 'difference from' something else.