EARTH’S ROCKS By Hayden Nolt

What Are Minerals? Minerals are natural solid substances that can form as a crystal.

Ways to Identify Minerals One way is to look at its streak.The streak test is when you rub a mineral on an unglazed tile and the color of the powder left behind is the streak.The streak is sometimes the same color as the mineral but it also can be a different color.Just like pyrite,it leaves a greenish or blackish brown streak.

Ways to Identify Minerals Another way is if the mineral shows florescence.Florescence is if the mineral glows under ultra violet light.Calcite and florite are examples of this property.

Ways to Identify Minerals The crystal shape is another way.A mineral’s atoms are arranged in a pattern that repeats and creates the shape.Six types are Triclinic, Monoclinic, Orthorhombic Crystal, Tetragonal, Hexagonal, and Cubic Crystal.

Ways to Identify Minerals Cleavage is also used.Cleavage is how a mineral breaks.A mineral usually breaks on the surfaces parallel to the crystal faces.

Ways to Identify Minerals A minerals hardness can be tested with common objects such as a penny,pocket knife, and even your fingernail.If you can scratch a mineral with your fingernail it is about a 2 on the Moh’s hardness scale.If you need a penny to scratch a mineral it is probably about a 3 on the Moh’s hardness scale.

Moh’s Hardness Scale The Moh’s Hardness Scale is a scale that classifies rocks.The scale goes from 1 to 10.

Igneous Rocks Igneous rock forms when melted rock cools and hardens.This melted rock deep within the earth is called magma.There are two different types of igneous rocks.One is intrusive rock, this rock cools under ground and takes a long time.This creates large crystals.They have a very coarse texture.Extrusive is the other kind this rock cools above ground.The crystals in this rock are smaller and they have a more fine grained texture.

Sedimentary Rocks  Sedimentary rocks form when layers of sediment settle and then bind together.Sedimentary rocks can begin to form when a bigger rock breaks into smaller pieces through weathering.Wind and water then move those pieces to new places and over time sediment will build up.Then the layers are squished together to form rocks.Shale and sandstone are formed this way. Sedimentary rock can be formed when the minerals in water form crystals and become solid.Ocean animals form their shells this way.

Metamorphic Rocks Metamorphic rock forms when Sedimentary, Igneous, or Metamorphic rock are changed by high temperatures,high pressure,very hot water,or all of them.The new rock is a metamorphic rock.

ROCK CYCLE

Facts Did you know that ancient Egyptians used powdered lapis lazul as eye shadow? Did you know feldspar makes up more than 50% of the Earth's crust? Did you know that geodes are dull balls of igneous or sedimentary rock on the outside, but contain beautiful crystals on the inside?

Facts Many minerals form beautiful crystals, but the most prized of all are gemstones. Uncut gems are often fairly ordinary looking. It's only when they are cut and polished that they obtain the brilliance and luster that makes them so valued. Unpolished and uncut gemstones Polished and cut gemstones

Facts  Limestone forms from pieces of seashells and dissolved shells,bones,and other materials that collect on the bottom off shallow oceans.  If a series of sedimentary layers are not overturned,the oldest layer is always at the bottom and the youngest layer is always on top.

BIBLIOGRAPHY e/earth/inside-the-earth/minerals-gems/ e/earth/inside-the-earth/minerals-gems/ SCIENCE by Scott Foresman

THE END I hope you know more about rocks now than you did before.