Opposites {Rubapphire AU}

Ruby Burns and Sapphire Frost know of each other. They've seen each other around school, they even have hung out together due to their friends having the same friends as them. Yet Sapphire and Ruby never really have talked. Nor do they take the liberty to get out of their comfort zone, but why is it whenever they see each other or hear each others name they have an attraction? But, come on they are complete opposites. That attraction can't mean something, can it?

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To be clear, Ruby and Sapphire are human. All Gems are human.