Of all the natural stones that you can choose for flooring granite is by far the hardest material and the most hardwearing. It is also resistant to staining and acid and alkaline chemicals. This is the reason it is the kitchen worktop of choice and the flooring material of choice.
Despite its hardness it is still capable of being scratched by quartz. Quartz is sand like material which makes up the biggest proportion of dirt brought into a building on the underside of footwear. Traffic going over this then moves the small particles of sand over the surface of the granite causing minute scratches. The scratching effect on granite will be much less than that on marble for instance but non-the-less it still scratches.
This effect can be minimized by the correct maintenance programme. A typical maintenance programme for granite flooring would be to dust mop the floor each day to remove these particles of dirt and once or twice a week depending upon traffic wash the floor with stone soap. This reseals the floor and enhances the colour. This is then wet vacuumed up and the floor then washed with pure water which is also wet vacuumed up. This wet vacuuming prevents the possibility of water staining.
Once per week or once every other week, again depending upon traffic the floor is misted with a crystallising agent and buffed at high speed. This removes the minute scratches and restores the shine to a floor which may be dulling very slightly in areas of high traffic. Then once per year it can be shined using a more abrasive crystallising compound and a slow speed buffer with non-rusting steel wool pads.
If this regime is followed then the shine on the granite floor should last for as long as you require it.
If the floor becomes neglected and is not cleaned correctly then it will slowly become dull and the scratching will build up enhancing the dull effect. If this was a marble floor then the scratching would be greater and could be removed and the shine restored by using diamond grinders on a slow speed buffing machine. However successful re-grinding of granite cannot be achieved. It can be re-ground using the diamond technique and made shiny but quite often it causes a colour change in the granite which is obviously not acceptable to the customer.
This regrinding process which for marble might take about 30 minutes per square meter for granite, being much harder takes about two to three hours to achieve any sort of shine.
In the processing plants marble is ground for about 40 minutes to achieve the high gloss effect. Granite on the other hand will be ground for several hours to achieve the same effect. There is no way that once the granite is in place this process can be replicated.
Consequently if you have a granite floor and it dulls and somebody offers to restore the shine by re-grinding it do not bother. You will end up with a floor that may be shiny but has probably changed colour and it will have cost you a small fortune. Take care of it from the outset and you will never be in this position.