mylonite

American  

[mahy-luh-nahyt, mil-uh-] / ˈmaɪ ləˌnaɪt, ˈmɪl ə- /

noun

1. Geology.  a rock that has been crushed and sheared to such an extent that its original texture has been destroyed.

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mylonite British  

/ ˈmɪlə-, ˈmaɪləˌnaɪt /

noun

1. a fine-grained metamorphic rock, often showing banding and micaceous fracture, formed by the crushing, grinding, or rolling of the original structure

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mylonite Scientific  

/ mī′lə-nīt′ /

1. A fine-grained laminated metamorphic rock in which preexisting minerals have been partially pulverized and drawn out into bands. Mylonite forms along geologic faults where shearing and grinding of rocks takes place.

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Etymology

Origin of mylonite

1885–90; mylon- (representing Greek mýlos mill) + -ite ¹

Example Sentences

In the three highest sandstone layers, the tools were all made of mylonite, a fine-grained igneous rock; the fourth layer contained tools of quartz, and among them were bones of strange animals: a giant hippopotamus, pigs 6 ft. tall, and a short-necked giraffe-like creature with antlers.

From Time Magazine Archive