COOL IMAGES: Rocks for Microscope Jocks

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Science  09 Apr 1999:
Vol. 284, Issue 5412, pp. 219
DOI: 10.1126/science.284.5412.219d

“Black minerals all look alike,” notes University of North Carolina, Chapel Hill, geology professor Allen Glazner. To the naked eye, that is. Pop a thin slice under a microscope bathed in polarized light and you'll see dazzling images like clinopyroxenite, formed from igneous minerals called pyroxenes that slowly cooled under pressure and formed coarse crystals. The image comes from an electronic atlas of igneous and metamorphic rocks (all rocks except sedimentary) created for Glazner's classes by grad student Kent Ratajeski. The 40 or so mineral “microtextures”–from blue threads of muscovite sandwiched between quartz, to red biotite and rainbow-colored talc—show there's much more to rocks than meets the eye.

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