The Granite countertop industry uses various types of stone that are labelled under the heading Granite.  The fact is, there are many varieties of stone that have different compositions.  For some homeowners, these differences are of little concern other than for aesthetics. 

Stones that are used to make countertops have a long and complex journey to finally end up in your kitchen. The process starts when magma from the mantle of the earth is pushed up through the crust and begins to solidify.

 

Magma that doesn't reach the surface, but cools over a very long time period is called intrusive igneous rock and this is where the true granites are formed. 

As the magma is slowly cooling crystals of various minerals begin to differentiate themselves. This leads to the beautiful crystal patterns and colour spectrum of granite.


 

If the magma spills out onto the surface from a volcano and hardens, it is called an extrusive igneous rock.  Examples of this are Basalt and Gabbro. These are generally darker in color with smaller crystals. This is where many of the black or dark
"granites" are formed. Much of the earth's continents are basaltic in nature.

El Capitan, Yosemite Valley- One of the most famous granite formations in North America.  


Basalt Columns- As basalt cools it sometimes crystallizes
into hexagonal columns many feet long.


 
 


 

 
 

Other minerals that occur in granite are horneblende, muscovite mica, and garnet.
Gneiss is a metamorphosed granite type rock that shows the melting and stretching of the original crystals and can lead to veining and striations. Depending on the amount of metamorphosing the alteration can be slight or dramatic.

 
 

Migmatites are an interesting type of rock that can have very dramatic veins and swirling folds of many colours.  They are a gneiss mixed with intrusive granite.
A lot of the beautiful veined granites from Brazil are of this type.



Some countertops are made from sedimentary rocks such as limestone, onyx and metamorphosed rocks such as Marble and Quartzite.


 
 
 
 
Granite is quarried from all over the world in countries such as Brazil, India, China, Canada, Norway, USA, and Saudi Arabia.  It is pulled from the earth by cutting large blocks out of the surrounding rock and then transporting to facilities for processing.

This includes cutting to dimension, slabbing into thin sheets and polishing to a fine finish. The slabs are then ready for fabricating into stunning countertops.