Text: "You melt the mantle and you get olivine basalts; you melt them again and you get basalt; you melt that and you make andesite; you melt that and you make dacite; you melt that and you make granite," said Christensen. "Every time you re-melt a rock, the first thing to come off is the silica, so each time you melt it, you're refining the silica." On Earth, such mineral evolution generally occurs as primitive volcanic rocks get folded back into the planet's crust, re-melted and refined as faster melting components like silica separate out of the original material - a process known as mineral fractionation.

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