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| | Outdoor Recreation: Rock Hounding |
 | | Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. |
 | | Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot, mineral-rich fluids or, more commonly, some combination of these factors. |
 | | In metamorphic rocks some or all of the minerals in the original rock are replaced, atom by atom, to form new minerals. |
| www.desertusa.com /geofacts/rock_met.html (344 words) |
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