Using granite for house signs and kitchen countertops is becoming more and more popular, but do you really know what granite is?
Granite is simply a very hard type of rock or stone, it is mined from the ground or mined or cut from the side of mountains, this is called quarrying. The goal of the quarry is to produce large rectangular blocks, some of these blocks can be huge and weigh up to twenty tons! Try to imagine a 6-foot by 6-foot by 12-foot block of stone made of one of nature’s hardest and densest materials.
Now let’s be clear, this is the same stone or rock found in our rivers and on many of our beaches along our coastline, especially in Scotland, Cornwall and Devon. Those rocks have been broken and shaped by millions of years of glacial activity, but many of them are granite just like our blocks.
The blocks are now cut into sheets of a usable size, the saws are massive beam saws with rows of parallel diamond-tipped blades that move back and forth water lubricated, the blades cut through the granite block like a cutter of bread cutting a slice. bread! Sounds simple, right, but granite is incredibly hard, the saws make a deafening noise, and each block takes days to process.
Until this stage the whole thing is a leap of faith, remember no one has ever seen this million year old piece of granite, if the stone is seriously flawed or not of an acceptable color all the work done so far will be wasted . be the first opportunity to see the color and markings of the stone.
Freshly cut slabs are called sparse, they have a rough, pitted face, covered in saw marks, it is difficult to even see the actual color, but by pouring water over the face, the color and marks become visible and it is possible to see the exploration potential.
The rare ones are now going to be polished, they are put on polishing machines that used to be called Jenny Linds, they are rotary polishers with large rotating heads that can be changed with different grades of diamond abrasives.
I’m not sure if the modern giant computer controlled versions have such a quaint name, but other than the computers name and size, the principle is the same.
Starting with a coarse grade to remove the worst marks and gouges, the polishing head is moved back and forth over the face of the granite in a smooth, controlled pattern for hour after hour, as each new grade is applied to the color. and the nature of the granite becomes more apparent, until with the final superfine grades, the granite takes on its brilliant shine, the amazing patterns and colors now seen in all their glory.
But how hard is granite? Granites are almost impossible to scratch deeply with anything other than high grade steel, tungsten, or diamond. Granites are extremely resistant to staining, one of the few things I have found to stain some granites is beet juice. Although you have to leave it on for some time for it to do any real damage. And lighter colored granites can be stained with rust from dripping from gutters etc. Granites are remarkably resistant to the effects of rain and sun, and most corrosives found in the home have little effect.
I have been a mason for forty years, but I never cease to be amazed by this miracle of nature, I often wonder who was the first man to try to polish a piece of this super hard stone, whoever he was, he was a genius!
