Granite has many applications, the most common of which is as a smooth surface. It is mined as a dimension stone, cutting it into blocks and slabs for decorative and structural purposes.
It has been used for centuries as such, and it is the most abundant type of rock on the planet. It can be used for paving, flooring, gravestones, building-facing stones, and fireplace surrounds.
However, due to its strength and durability, it is most frequently used for workspaces like vanity tops and countertops.
In bathrooms and kitchens all over the country, granite is still one of the most popular countertop materials. It is also one of the most popular countertops at Keystone Granite. In this article, we’ll go over some specifics about this material and how it’s made to help you understand why it’s so popular.
What is Granite?
Granite is an igneous rock primarily composed of quartz, feldspar, micas, amphiboles, and trace minerals.
These minerals and their abundance and alteration contribute to the variety of colors and textures found in granite countertops. Granite is a plutonic rock composed of 10 to 50% quartz (typically semi-transparent white) and 65 to 90% total feldspar (typically pinkish or white).
As an “intrusive” igneous rock, granite forms in place as molten rock cools. Mineral crystal size generally increases with cooling rate, with K-Feldspar megacrysts growing to more than 5 cm in rare cases.
The term “igneous” refers to rock formed by the hardening of molten magma and can be seen as large crystals in polished and processed rock. Granite is formed by being buried beneath kilometers of rock and sediment, which produces enough heat to melt the rock.
And last but not least, it is called “granite” because of the granularity of the patterns.
Because granite was formed under extreme pressure, it is extremely strong. As a result, it is incredibly dense and almost entirely nonporous. Water and other fluids do not easily penetrate past the surface, but when they do, they leave a stain, which geologists refer to as “poor primary permeability.”
Of course, the granite we see today is close to the surface and was therefore uplifted at some point, resulting in the erosion of overlying sediment.
As the granite transitions from high pressure and temperature to atmospheric pressure and temperature, it may slightly expand and crack. Combined with seasonal temperature variations, this can lead to weakened and less desirable granite for use as countertops.
As a result, you should hire a professional installer to assess your requirements for a new granite countertop. Remember, the greater the percentage of quartz in the slab, the longer it will last.
How is Granite Formed?
A variety of conditions resulted in the formation of granite. Some granite formed in rifted continental or oceanic crust regions, but the vast majority formed when continents collided with oceanic crust, and continents merged. As a result, it is most commonly found in areas of high tectonic activity, such as mountain ranges and volcanic areas.
Additionally, granite can be found in smaller bodies, like dikes and sills, which are created when magma is injected into fissures or cracks in the neighboring rocks.
Granite formation typically involves three major stages:
- Melting: Granite is formed by melting pre-existing rocks, such as sedimentary or metamorphic rocks, deep within the Earth’s crust at high temperatures and pressures.
- Magma formation: A molten substance known as magma is formed when these rocks melt. Magma is less dense than the nearby rocks and rises towards the Earth’s surface.
- Crystallization: As magma cools and solidifies, large mineral crystals form that interlock with one another to form the distinctive coarse-grained texture of granite.
Overall, plate tectonics processes and the long-term movement of the Earth’s crust are closely related to the formation and occurrence of granite. High pressures and temperatures cause rocks in the Earth’s crust to melt and change into new rock types, including granite. These processes can take millions of years to complete, forming today’s breathtaking landscapes.
Distribution of Granite Deposits in the World
Rocks like granite are widely dispersed and can be found on every continent in the world. It is frequently connected to tectonically active regions like mountain ranges and volcanic regions. Here are some major granite deposits from around the world:
- North America: The United States and Canada both contain significant granite deposits, with the Sierra Nevada in California, the Rocky Mountains in Colorado, and the Canadian Shield in Ontario and Quebec being particularly noteworthy.
- South America: South America’s Andes Mountains range contains a variety of granitic rocks, including the famous Inca citadel of Machu Picchu in Peru.
- Europe: The Scottish Highlands, the Iberian Peninsula, and the Alps are just a few of the prominent granite deposits found in Europe.
- Africa: The Cape Granite Suite in South Africa and the Nigerian Younger Granite ring complexes are two significant granite deposits on the African continent.
- Asia: The Himalayan Mountains range, the Chinese Red River batholith, and the Korean Peninsula are just a few regions in Asia where granite deposits are abundant.
- Australia: The Yilgarn Craton, which covers much of Western Australia, is a significant granite deposit in Australia.
- Antarctica: Granite is also present in Antarctica, serving as the bedrock for much of the interior.
FAQ
- When did granite form on Earth?
Throughout all geologic eras, granite has been inserted into the Earth’s crust; the majority of it is Precambrian in age. Granite is the most prevalent basement rock beneath the relatively thin sedimentary veneer of the continents and is widely distributed throughout the Earth’s continental crust.
- Is granite made from lava or magma?
To answer this question, we need first to understand the difference between lava and magma. Scientists refer to magma as underground molten rock and lava as molten rock that breaks through the Earth’s surface.
As explained in this article, for granite to be formed, first, the crystallization process should occur. This means if the magma reaches the surface and flows out onto the surface, it would not be “granite.” Ultimately, it is safe to say that granite is not made from lava.