Distinguishing
Among
Igneous, Sedimentary, & Metamorphic Rocks
Can you identify if a rock is igneous, sedimentary or metamorphic?
Igneous Rocks: nonfoliated, crystalline textures
composed of several common minerals.
Sedimentary Rocks with clastic textures – may
contain some igneous minerals, but also non-igneous minerals (e.g., clay).
Sedimentary Rocks with crystalline textures
– composed of minerals not common in igneous rocks.
Foliated Metamorphic Rocks: distinguished from
igneous and sedimentary rocks by foliation. Some contain minerals only found
in metamorphic rocks (e.g., kyanite, staurolite).
Non-foliated Metamorphic Rocks usually consist
mostly of one mineral (e.g., quartz, calcite).
Problem Rocks:
Shale vs. Slate
Quartz Sandstone vs. Quartzite
Limestone/Dolostone vs. Marble
Graywacke vs. Basalt
Mudstone vs. Tuff
Conglomerate /Sedimentary
Breccia vs. Volcanic Breccia
