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Color versus gray-scale images of a zircon. Sample is a finely layered quartzofeldspathic gneiss from the Llano Uplift of central Texas. Are the zircons of igneous or metamorphic origin? I'm leaning towards igneous with a narrow metamorphic rim. No evidence of a abrasion by transport is present. Based on these interpretations I would suggest that the protolith of the rock was volcanic, although volcaniclastic can not be ruled out.