 | Tell me, Lulu, are there any rules governing which minerals occur together in a rock?! Or can any mineral occur in any rock? Can the mineral composition of a rock provide a clue as to its origin? In short, Lulu, is the mineralogy of rocks orderly or is it all random?!" |
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 | "There's both orderliness and there's randomness!" |
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| "Oh great!! No doubt you'll explain?!" |
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