If you are in the market for new granite countertops, you’ve probably already looked at a ton of photos online and most likely visited a few showrooms. If you are like me you have perhaps wonder where does the granite come from and how do they make it look so pretty?
In the post, I will try to explain how the rock is removed from the Earth and turned into beautiful stone countertops.
Where Do We Get Our Granite?
The formation of granite occurs when magma crystallizes slowly below the Earth’s surface. Granite is composed of mainly natural quartz and feldspar with traces of amphiboles, mica, and other organic minerals. At their earliest stages, your granite countertops were just molten magma. The color and patterns of each type of granite are a result of the distinct mineral composition. These color variants are a red, pink, grey, or white color with dark grains in the pattern. Some of the most extraordinary granites will include colors like blue, green, black, and gold.
Brazil supplies the majority of the world’s granite for countertops, followed by Italy, India, and China. Because of the process in which granite forms, it will have a different color at every mine. There is one granite known as Van Gogh or Blue Fire that has incredible blue color. Van Gigh is only available in Brazil.
Mining the Granite
Granite is located close to the Earth’s surface, allowing mining to take place in shallow quarries. The granite formation is typically varied large, and the rock will need to be cut into transportable pieces to be processed. The sectioning of granite happens by drilling small holes in the size that will be transportable — by precisely measured explosives, placed into the holes. When detonated, the block will separate from the bedrock without cracking.
The blast is designed to direct the block onto a bed of sand to minimize any unintentional damage. Large equipment is used to lift the large chunks of granite and load them into heavy-duty trucks. Once loaded, they will be transported for further processing.
Most of the works granite will ship to Italy, India, and China, where they have extensive facilities with specialized equipment for cutting the granite into slabs.
From Block to Granite Slab
Once at a stone cutting facility, the large block of granite will be cut into slabs, split into 2 or 3cm pieces. The machine does not cut one slice at a time but multiple slabs at once. The machine can have numerous circular blades or diamond wire blades that will cut through the block of granite similar to an egg slicer. It can be a long process, taking up to an hour for these blades to go through one foot of stone. Imagine how long it takes to cut through an entire 10′ x 5′ x 10′ block of granite
Recent innovations like the use of diamond wire cutting saws and other technological advances have increased the speed and accuracy of this process. Thus, leading to faster production and lower cost to produce granite, resulting in better consumer prices.
Today we see much more granite used in middle-class homes. In years past granite counters were not affordable to be used in the same houses.
Polishing to Reveal the Natural Beauty
Polishing the granite’s surface will bring out the natural colors and patterns. Also, the surface will become smooth to the touch.The machines that will polish the slabs have large, diamond polishing pads. The diamond pads remove small amounts of the granite. There are several steps in the polishing process, and each one will use a lower grit diamond abrasive. Each of these steps slowly brings out the shine in the granite. Only the one side of the slab is polished, while the edges and sides are left unpolished.
Ready for Distribution
Once the slabs are polished and bundled into bundles of 6-7 slabs. Typically they are bundled in the order they were cut from the block. Allowing the bundled slabs will have consistent patterning and color. The bundles are then packaged onto a shipping container and transported to the US on a Freighter.
The Slab Yard
If you are working with the right installer, they will have you go to a slab yard to select the slabs that will be going into your home. You may have looked at samples and displays in showrooms, but you will want to look at the slabs before you decide on a type of granite. The examples that you see are a small part of a slab and will not fully display what the granite that you will be selecting. Seeing the full slab is the only way to get a good visual.
There are many slab yards located all over the country. Some provide installation, while others do not. In any case, you would be best to find an independent granite installer to get the best price on top-notch installations.
Fabricating Your Granite Countertop
The first step the fabricator will take is inspecting the slabs you selected at the slab yard. Granite is a natural product and is likely going to have flaws that are common to that particular granite. Some of the blemishes include polyester resin fill, dry seams, pits, black spots, and natural directional veining, conglomerates of feldspar or mica 9looking like knots). These blemishes make the stone unique and beautiful. Occasionally you find a particular characteristic unacceptable. In this case, you should ask the granite fabricator to avoid using those spots in the fabrication of the countertop.
Before templating, one last final inspection of the granite slabs will need to occur. The final review helps to identify any areas of the slab that you will find unacceptable. The granite fabricator will note those areas by marking them, so they are avoided during templating. Thus, helping minimize waste and cost.
Laying Out The Template
After the final inspection, the slab is laid out, and the previously designed templates are laid out on the stone. The templates will be arranged to ensure the best appearance concerning the granites vein texture and color. The templates are also used to guarantee proper flow for the different countertops in your plan. This critical in granite and marble because of the distinct grain that they have. This is where the experience of the fabricator will shine. A great fabricator will display a mixture of expertise and artistry in his design. When templated and laid out correctly, it is just that, a piece of art.
Cutting The Stone
The granite will then be cut using either a water jet or a bridge saw. Until recently, the bridge saw was the tool of choice. However, in recent years the “saw jet” has become the most popular choice. It utilizes a combination of a water jet, and diamond saw to cut the granite.
The bridge saw used a segmented diamond blade. The hydro-jet cuts using a mixture of high pressure water and garnet particulate as an abrasive to help cut. The benefit of the hydro jet is the ability to cut circles, radius, and complicated patterns. Where the bridge saw is only capable of cutting straight lines.
A saw jet is the most recent cutting tool to come to the aide of the granite fabricator. It combines the best of both a bridge saw and a hydro jet. It uses a program to cut the countertop, utilizing the saw on straight sections and the hydro jet on curved or more intricate areas. Once the countertop pieces are removed from the large slab, they are moved to a CNC machine for further fabrication.
Fabricating The Countertop
At this step, the CNC (Computer Numerically Controlled) machine will cut out the holes for sinks, faucets, and outlets. Initially, the granite will be cut and leaving approximately 1/16″ of excess material remaining. The CNC machine will be programmed to calculate the size piece of stone that is on the work surface. Multiple pieces of stone can be processed at once. The CNC machine programmer will input the locations of each piece on the table. Every stone has unique working characteristics making it very important to have a knowledgeable CNC operator cutting your countertops. It is a true mix of artistry and technology when producing the finished product. Each stone will require different cutting speeds and feeds to produce a beautiful finish countertop. Without this experience, the end product may not turn out as expected.
After the holes are cut in the granite, the CNC machine will shape the final edges. The CNC machine is capable of producing various types of edges. Once the edges are complete, the countertop is ready for the final polish.
Polishinh The Surfaces
Polishing the stone is one of the final steps in the granite countertop fabrication. When the granite slab was delivered to the fabricator, only one side of the granite was polished, the face. The face is typically not polished at the fabricators, but what does need to be polished are the edges. During the CNC operation, the countertop edges were cut. These freshly cut edges will need to go through a 7 step polishing process. The standard polishing process calls for the use of diamond polishing pads. The pads will use increasing grit from 50 to 3,000 to polish the edge to the appropriate sheen. The polishing will be performed on another CNC machine. Starting with a diamond polishing pad of 50 (the most aggressive), then working up to 3,000(the finest). The CNC is programmed to shape and polish simultaneously. Resulting in a beautifully shaped and polished edge. If you get a scratch in your granite, you can manually perform this process repair it.