yoga11912

I have been a stone and marble mason for forty years and for all of my working life I have been obsessive about keeping potential stain creating products out of my workshop and away from my stocks of stone , marble and granites. It therefore follows that my experience of stain damaged materials have been limited to rare accidents over the years. And most of these have involved marble, in fact I have been unable to recall a single occasion when we had an example of granite staining.

With the increasing use of granite for kitchen worktops and my current specialty house signs, I have recently had cause to consider just how stain resistant is natural granite? To try to answer this question I set up a small experiment to try to deliberately introduce stain damage to a piece of granite using products found in the average kitchen.

The Experiment:

I used a piece of Nero Impala granite 20mm thick with a highly polished face. Nero Impala is a tight grained, mid to dark grey mottled granite from South Africa. I chose this type of granite as being a typical mid-range granite in terms of hardness and colour. This piece has a normal polished finish and has never been sealed to prevent staining.

I lay the piece of granite on a horizontal surface indoors and left it to thoroughly dry out for a couple of days.

I stuck a number of small labels across the face of the granite and next to each label introduced one of the chosen staining agents and as I introduced each new product, wrote he name of the product on the adjacent label in pencil. (Tip: if you are labelling something in conditions where the labels may get wet, use pencil.)

I then left the granite and the staining agents to do their worst for a full eighteen hours.

The Staining Agents: (and my expectations of them)

1. Vegetable Oil: Oils have always been taboo around marble workshops and are guaranteed to stain marble. I was certain these oils would leave at least a wet looking stain on the granite.
, 2. Same as vegetable oil really but different oils do have different characteristics and olive oil is common to most kitchens.
3. Soy Sauce: I thought the combination of the dark colouring and the potentially corrosive nature of the vinegar base would be a serious contender to cause damage
4. Vinegar: I expected the vinegar to act as a corrosive and at least slightly degrade the polish.
5. Beetroot Juice: Beetroot juice is one of the most deadly stains I know of, as any housewife knows and I was pretty sure that this would soak in and leave a nasty purple stain.
6. Ketchup: Contains oil and vinegar and a lot of colouring is superb at staining kids clothes!
7. Tea Bag Wet: Tannin is a strong staining agent I expected this to leave at least a surface stain and an underlying water mark.
8. Washing up Liquid: Soap will stain marble so definitely worth a try.
9.Scotch Whisky: Don't panic! I used the cheap cooking stuff. I really was confidant that this would degrade the polish. On marble any strong alcohol spirit will cut through the surface polish so I assumed the same would be true of granite.
10. Red Wine: We all know how pervasive red wine stains can be. And any excuse seems good to open a new bottle!
11. Lemonade: You may be suprised to know that lemonade will also destroy the polish on marble if left for long enough, over eighteen hours I was pretty sure it would do some damage to the granite.
12. White wine: Ok I didn't think this would do any harm but it was open anyway!
13. Tabasco Sauce: Hey! this stuff burns throats like anything so why not granite ?
14. Lemon Juice: Very acidic of course, and if the lemonade does the trick neat lemon juice should work even better ( or worse depending on your viewpoint!).
15. Half an Orange: Citric acid and orange colourant, should be interesting.

Ok that's the lot, I was pretty confidant that the oil, the beetroot and the whisky would cause some damage but I was not sure about the others.

After the eighteen hours I mopped up the residue of the various staining agents and cleaned the surface of the granite with a normal kitchen spray cleaner and left it to dry for ten minutes.

I then inspected the granite in daylight for damage to the polish from corrosive acids and staining from the colourants and the oil based products.

The Result:
Nothing! No staining no degrading of the polish not even the wet looking stains I was sure would be caused by the oils and the wet agents. This was a real surprise, eighteen hours is a long time and under normal domestic conditions any spillage would be cleaned up much sooner.

This is a really impressive result for the granite but a bit of a blow for me as I had hoped to write further articles on removing stains and re-polishing alcohol spots!

Still I mustn't be too surly about it, I have always been an admirer of the qualities of granite but now I can quote the stain resistant virtues of the stuff with great confidence.

One caveat however, there are many different types of granite and I cannot guarantee that this performance will be as impressive with them all, or that I have tried every potential staining or corrosive product, but I have no reason to think that other granites are more susceptible to damage or that any other agents pose a bigger threat.

Steve Walker has been a craftsman in stone and marble for 40 years. In his long career has practised as a stone mason, letter cutter, restoration carver, marble mason, and fireplace designer/manufacturer.

He now specialises in engraved stone, granite and slate house signs as: http://www.stoneengravings.co.uk StoneEngravings, Engraved Natural Stone House Signs.