Are you ready to rock?
By: Alicia Crespo
What is a rock?
Igneous rocks are formed by being melted and solidified. They are formed either inside or outside a volcano. The two main types are Intrusive and Extrusive. Intrusive rocks form slowly and have large crystals. Extrusive form quickly and have small crystals.
Sedimentary rocks are formed by cementing and compacting sediments. They are formed on the Earth's surface. The main types Clastic, Bioclastic, and Crystalline. Clastic are made of different sized particles cemented together. Bioclastic are made of animal or plant remains. Crystalline are formed when materials are left behind after water evaporates.
Metamorphic rocks are formed when they are exposed to heat and/or pressure, with no melting. They are formed deep within the Earth, near the core. The two main types are Foliated and Non-foliated. Foliated have an alignment of minerals.
TYPES OF ROCK
2.) Texture- Fine; Crystal size-Non-crystalline
4.) Density- Low; Color-Lighter; Mineral composition- Felsic
Grain Size: Pebbles, Cobbles, and/or boulders embedded in sand, silt and/or clay.
Composition:Mostly quartz, feldspar, and clay minerals.
Comments: Rounded fragments
Grain Size: Fine
Comments: Low-grade metamorphism of shale.