AN INTRODUCTION TO GRANITE
Granite for house signs, Memorials and of course kitchen tops is becoming more popular, but do you know what granite really is? Granite is quite simply a type of very hard rock or stone, it is dug from the ground or blasted or cut from the side of mountains. This process is called quarrying. The ideal of the granite quarry is to produce large squarish blocks.These blocks can be huge and weigh up to many tons! Try to imagine a block of stone 6 feet by 6 feet by 12 feet made of one of the hardest and most dense materials in nature.
Now let's be clear. This granite is the same type of stone that makes up the pebbles in some rivers and on many of our beaches, especially in Scotland, Cornwall and Devon. Those granite pebbles have been broken and shaped by millions of years of glacial activity. However to produce commercial sizes of granite requires quarrying. Quarried blocks are sawn into sheets of a useful size on massive beam saws with rows of parallel diamond tipped blades that move backwards and forwards lubricated by water. The blades slice the granite block rather like a bread slicer cutting up a sliced loaf! Sounds simple doesn't it but granite is incredibly hard. The saws are deafeningly noisy and the process for each block takes days.
Up to this stage the whole business is an act of faith, remember no-one has ever seen this piece of million year old granite.
If the stone is seriously flawed or not an acceptable colour all of the work so far is wasted. This will be the first
opportunity to see the colour and markings of the stone.
The newly cut slabs are called scants. They have a rough and pitted face covered in saw marks. It is difficult to even see
the real colour but by throwing water over the face, the colour and markings become visible and it is possible to see the
potential of the scant.
The scants now go for polishing on huge rotary polishers with large spinning heads that
grind the surface of the granite with different grades of diamond abrasives.
Starting with coarse grades of abrasive to grind out the worst marks and grooves the polishing head moves backwards and forwards over the
face of the granite in a controlled and even pattern for hour after hour. As each new grade is applied the colour and nature
of the granite gradually emerges, until with the final superfine grades the granite takes on its brilliant polish. The
amazing patterns and colours are now seen in their full glory.
Just how hard is granite? Granites are difficult to scratch deeply with anything other than high grade steel, tungsten or diamond. Granites are extremely resistant to staining, oil is one of the few things I have found will stain granite. Lighter coloured granites may be more prone to staining than darker colours and may stain with beetroot juice or rust . Granites are extraordinarily resistant to the effects of rain and sun and most corrosives found around the home have little effect. I have photo's of granite memorials over one hundred years old that still retain a perfect polished surface! I never cease to wonder at 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 an unsung genius!