Identifying Rocks

Earth Science - Middle School

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Identifying Rocks Rocks are solid, naturally occurring substances composed of one or more minerals and other matter. Rocks are classified into three groups according to how they were formed: igneous, metamorphic or sedimentary. COLOR: reddish brown with some gray DESCRIPTION: large random crystals and no layers GRAIN: large, coarse grains or clasts (easily visible to the eye) COMPOSITION: Some minerals found in this rock are quartz, feldspar and mica. Geologists use physical properties and characteristics of rocks to help identify them. Some of the properties of the sedimentary rock breccia are described below. This rock is formed when eroded rock fragments pile up and are compacted together. © Copyright NewPath Learning. All Rights Reserved. 94-4676 Visit www.newpathlearning.com for Online Learning Resources. Some photos courtesy of USGS and NPS. Igneous Rocks Sedimentary Rocks Metamorphic Rocks Igneous rocks form when liquid rock (magma & lava) cools and hardens. Igneous rocks may or may not have visible crystals depending on how long they took to cool. Sometimes lava is frothed up with gases, producing a very light weight rock called pumice. pumice obsidian granite basalt Metamorphic rocks are rocks that have changed as the result of intense heat and pressure deep in the Earth’s crust. Foliated metamorphic rocks have mineral grains arranged in parallel layers Nonfoliated metamorphic rocks have mineral grains arranged randomly. sandstone conglomerate limestone shale gneiss quartzite marble slate Sedimentary rocks are rocks that have been placed by weathering or erosion in layers. Over millions of years, these layers are compressed and cemented together. There are three categories of sedimentary rocks: clastic, chemical and biochemical or organic.
Identifying Rocks Pause and Review Describe and identify the following rock samples. © Copyright NewPath Learning. All Rights Reserved. 94-4676 Visit www.newpathlearning.com for Online Learning Resources. Color: ___________________________________ Grain: ___________________________________ Description: ______________________________ Composition: _____________________________ Type: ____________________________________ Name of rock: ____________________________ Color: ___________________________________ Grain: ___________________________________ Description: ______________________________ Composition: _____________________________ Type: ____________________________________ Name of rock: ____________________________ Color: ___________________________________ Grain: ___________________________________ Description: ______________________________ Composition: _____________________________ Type: ____________________________________ Name of rock: ____________________________ Color: ___________________________________ Grain: ___________________________________ Description: ______________________________ Composition: _____________________________ Type: ____________________________________ Name of rock: ____________________________ Color: ___________________________________ Grain: ___________________________________ Description: ______________________________ Composition: _____________________________ Type: ____________________________________ Name of rock: ____________________________ Color: ___________________________________ Grain: ___________________________________ Description: ______________________________ Composition: _____________________________ Type: ____________________________________ Name of rock: ____________________________