Rocks!! What is a rock? What do all rocks have in common? A ROCK is a mixture of one or more minerals and other various materials. *There are 3 main types of rock, each is classified by how and where they form

Quick fact:: 65% of all rocks on our planet are classified as Igneous Any rock that forms from lava or magma that has cooled is classified as Igneous. These rocks are also commonly referred to as “volcanic”. But remember, “lava” and “magma” are found in very different areas, so the rocks formed when they cool are different as well. Quick fact:: 65% of all rocks on our planet are classified as Igneous

There are 2 major types of igneous rock: Extrusive – Cools quickly on the Earth’s surface (lava). Typical characteristics of extrusive igneous rocks include a small crystal structure and a fine-grained texture. Examples include Basalt and Obsidian Intrusive – Cools slowly beneath earth’s surface (magma). Typical characteristics of intrusive igneous rocks include a larger crystal structure and a coarse grained texture. GRAVITY, PRESSURE AND TEMPERATURE DIFFERENCES DETERMINE DIFFERENCES IN A ROCK’S CHARACTERISTICS Examples include Granite and Porphyry

The crunching, folding, and resulting This process can work “backwards” too……All rocks can be melted into magma again as they return to the mantle, possibly to return as new igneous rocks in the future! But some rocks are buried deep within the earth to be exposed to the extreme temperatures and pressures found there without ever getting hot enough to rejoin a magma pocket. The crunching, folding, and resulting heat transforms these rocks into entirely different rocks with unique characteristics.

The 2nd type of rock formed on our planet is produced in this way. This is called metamorphic rock Metamorphic rock – Has changed form due to high heat and pressure beneath the Earth’s surface. It’s properties and characteristics change drastically as a result. Minerals are re-crystallized! These extreme forces can even turn COAL…… …..INTO….. DIAMONDS!!!!! Unfortunately, this particular example is a rare occurrence!!!!

Much more common examples of metamorphic rocks are: Original rock Metamorphic (new) rock Granite Shale Sandstone Limestone Gneiss Slate Quartzite Marble What do you think happens to the density of a rock as it goes through a metamorphic change? Texture? PREVIOUS KNOWLEDGE IN ACTION

Pressure closer to the Earth’s surface can also form new rocks When small particles come together sometimes they can be “squeezed” into Sedimentary Rock Sedimentary Rock – Rocks that form from layers of material (sediment) piling on top of one another. The bottom layers are compacted together because of the weight above them.

3. Chemical Sedimentary – Made from crystallized minerals. Examples: There are 3 types of sedimentary rock. They are different because of what they are made from: 1. Clastic Sedimentary – Made from rocks and small particles. Examples: Sandstone (made from grains of sand) Shale (made from clay particles) 2. Organic Sedimentary – Made from the remains of living things. Examples: Limestone (made from the skeletons and shells of sea creatures) Coal (made from tropical plant remains) 3. Chemical Sedimentary – Made from crystallized minerals. Examples: Halite – (salt) Gypsum – (water, sulfur, calcium)

1. A rock is a mixture of ___________ and various other materials. 2. Another word for Igneous rocks are __________ rocks. 3. Extrusive Igneous rocks cool on the Earth’s surface, while ___________ Igneous rocks cool below the Earth. 4. Extreme temperature and ____________ help form Metamorphic rocks. 5. The density and smoothness of a rock ___________ as it goes through the metamorphic process. 6. The 3 types of sedimentary rock are clastic, organic and ___________. 7. Limestone is an example of a(n) __________ sedimentary rock. Minerals Volcanic Intrusive Pressure Increase Chemical Organic