Difference Between Quartzite & Granite

Granite mineralogy
••• Jupiterimages/Photos.com/Getty Images

There are several differences between quartzite and granite. Granite gets its hardness from its quartz content, but quartzite contains more quartz per volume than granite, making it essentially a harder material. Granite is more abundant than quartzite; it is widely distributed throughout the earth’s crust and forms the foundation that underlies the sedimentary rock beneath most of the continents.

Formation

Quartzite is a metamorphic rock that forms from the joining of sandstone and quartz under intense heat and pressure. This material is often found where regional or contact metamorphism took place. Regional metamorphism is the process in which quartzite is formed under more pressure than heat, while contact metamorphism involves more heat than pressure. Sandstone is often compacted into quartzite when continents collide, filling in empty grains of sandstone with quartz. Granite forms at greater depths than quartzite, but similar to quartzite, granite requires some levels of pressure and heat to form. Granite is a type of igneous rock that typically forms underneath continents. It forms when liquid magma cools into existing rock formations.

Hardness

Quartzite and granite are both very hard materials, which lends to their many practical applications. Hardness can be measured on the Mohs scale of hardness. This scale, with a range from 1 to 10, designates harder materials with higher numbers. Quartzite offers an approximate value of 7 on the Mohs scale while granite offers a hardness value of between 6 and 6.5 on the Mohs scale. Quartzite is often employed in the creation of railway ballasts and borders for flowerbeds. Granite is often mined in slabs for the fabrication of tiles, gravestones and countertops. The quartz contained within these materials contributes to their hardness. Quartz offers a 7 on the Mohs hardness scale.

Components

Any rock that contains 10 to 50 percent quartz and offers an alkali-to-feldspar ratio between 65 and 95 percent is defined as granite. Granite typically contains a combination of quartz, mica, feldspar and hornblende. Biotite, magnetite, garnet, zircon and apatite may also be involved in the formation of granite if the materials are present. Quartzite is made out of sandstone, silica, iron oxide, carbonate, clay and a very large percentage of quartz.

Color

Granite can contain many different materials in its composition. Each component in granite can affect the overall appearance of the granite in terms of color. The color of granite can vary dramatically based on location. For example, granite mined in the eastern United States may offer similar properties to granite mined on the opposite side of the country but appear quite different. Feldspar, which can appear many colors -- from green to pink -- can greatly affect the color of granite. Quartzite in general appears white to gray. However, certain components, such as iron oxide, can vary the color of quartzite. Quartzite that is heavy in iron oxide may appear pink to red in color. Quartz can form in colors such as yellow, rose or brown, thus affecting the overall color of both quartzite and granite.

Related Articles

Limestone Chemical Components
The Characteristics of Slate
Interesting Facts About Quartzite
The Different Kinds of Missouri Stone Used for Flint...
Types of Rocks Found in the Himalayas
Types of Intrusive Igneous Rock With Large Crystals
What Are the Three Most Common Cementing Agents for...
What Are the Types of Rocks Found in the Appalachians?
What Is the Difference Between Sandstone & Limestone?
What is a Sardonyx?
Facts About Slate Rock
Difference Between Quartz & Calcite
Difference Between Continental & Oceanic Plates
Volcanic Rock Types by Mauna Loa
Difference Between Granite & Limestone
How to Identify Platinum in Ore Deposits
Rocks of Pennsylvania
A List of Extrusive Igneous Rocks
The Types of Rocks on Mauna Loa
Which Types of Granite Emit the Most Radon?

Dont Go!

We Have More Great Sciencing Articles!