Classification of Rocks
By Hailey Schneider
- Igneous rocks are formed by the cooling and solidification of magma or lava
- Igneous rocks are formed above ground as lava cools
- The main types of Igneous rocks are intrusive and extrusive. Intrusive Igneous rocks are formed from magma that cools and solidifies within the crust of a plant, surrounded by preexisting rock. Extrusive Igneous rocks form when magma makes its way to the surface of the earth.
- Sedimentary rocks are formed by cementing and compaction
- Sedimentary rocks are found on the surface of the earth
- The main types of sedimentary rocks are clastic, and bioclastic. Clastic sedimentary rocks are composed of broken pieces. Bioclasts are skeletal fragments of marine or land organisms which are found in sedimentary rocks.
- Metamorphic rocks are formed from heat and pressure with out melting
- Metamorphic rocks are formed inside the earth
- The main types of metamorphic rocks are foliated/banding, and non foliated. Foliated/banding metamorphic rocks are when pressure squeezes the flat minerals within a rock so they become aligned.
Three Types of Rocks
Sedimentary Rock Conglomerate
- The sedimentary rock conglomerate is inorganic
- The grain size of this rock is pebbles, cobbles, and/or boulders embedded in sand, silt, and/or clay
- The composition of this rock is mostly quartz, feldspar, and clay minerals; may contain fragments of other rocks and minerals
- This rock is mainly rounded fragments
Metamorphic Rock Schist
- The texture of this rock is foliated
- The grain size of this rock is fine to medium
- The composition of schist is mica, quartz, feldspar, amphibole, garnet, and pyroxene
- The type of metamorphism is regional where heat and pressure increases
- Platy mica crystals visible from metamorphism of clay or feldspars