Can
Granite and Quartzite Etch
Frederick
M. Hueston, Stoneforensics.com
One of the advantages of having a granite or quartzite top
is its resistance to etching. Many stone
fabricators recommend these stone for countertops due to the fact that they
will not etch with common acidic food and beverages. Acidic substances generally will not etch
these stone cause they lack calcium. Calcium is the main mineral found in
marbles and limestone. However, there is a substance they will produce an etch
like mark on not only granite and quartzite but also on glass. This is what we
call an alkaline etch. Alkaline are any chemical substance above 7 on the pH
scale. Many household chemicals such as cleaners, soaps and detergents are
alkaline in nature. Theses alkalis contain salts which can deposit on the
surface or in the pores of the stone leaving a white haze. A good example of
this is when your glasses in a dishwasher have a white cloudy film on them that
won’t wipe off. This is caused by the harsh detergents in dishwashing soaps.
The same reaction can take place on granite and quartzites.
How to remove Alkaline etching
Since an alkali is higher on the pH scale, an acid is needed
to counter act the alkaline reaction. So a mild acid is recommend to remove the
etch. Take a rag or paper towel and soak
it in white vinegar. Place the the rag on the etch and allow it to sit for
several hours. The acid in the vinegar should react with the alkali salts and
dissolve it. After several hours remove the rag and rinse the area with a
neutral cleaner and dry. Examine the area.
In some cases the stone may need to be repolished by a professional.
