Water absorption in weight

Hi Maurizio, I am confused about "water absorption in weight". Giallo Napoleone which I am considering is rated as o.2-0.3%. Is that good or really bad? I just don't understand these ratings. Can you explain? Thank you.

 

Dear Jennifer:

The way they determine the absorbency rate of stone is by taking a rough piece of the stone to be tested and weigh it. After that they submerge it in a container full of water and leave it there for 24 hours. They then pull it out, let it drip and weight it again. The difference between the “before and after” weight transformed in percentile is what makes the rating.

Unfortunately it is not so simple. 0.2% to 03% is the indication of a rather dense stone, but other factors may enter the equation that can be measured, such as the capillarity of a particular mineral structure, etc.

Furthermore, the processing of the surface of the stone (polished or whatnot) may further alter the rating by increasing the surface tension. Add to the mix the fact that the majority of “granite” slabs are resined nowadays, and you have a scenario where the absorbency rating has little bearing if any at all.

What to do to determine if a stone is appropriate for your purposes?

Run your own testing on a scrap piece of the very slab they will be using to make your countertop.

I hope you will understand the true spirit of what I'm about to say. It appears to me that like most other inquirers at this stage you seem mostly interested in the type of stone and/or its physical characteristics. It's human nature at work, I reckon! J

How about if I tell you that a certain stone is a good choice and then you get a low-grade slab or a doctored one? Trust me: the human factor is far more important than the stone itself and should be the only true deciding factor!

In an industry that's virtually unregulated, how good and reputable the fabricator who's is going to process the stone you'll end up choosing is far more important than the stone itself. None of the horror stories that get posted in this very site stem from the stone: they all stem from the fabricator. That is why I seldom make final statements about any one particular stone. There may be differences within the same stone (and I'm not talking about looks, here!) from one bundle of slabs and the next. The slabs may have also been either “doctored” (which is bad), or “resined” (which overall is good) by the factory, which would make a big difference. Even more important, what's a good stone in the hands of some “Michelangelo”?! And again: a reputable fabricator will only carry high-grade slabs, not some “special!”

We have available a very comprehensive article on “How to Shop for a Granite Kitchen Countertop” that will give you all the intelligence you need to venture yourself with confidence in the stone industry jungle, and it includes the world renowned “Lemon juice (and oil) test”, which will enable you to determine on your own the suitability of any stone you will consider! It does carry a small price tag, and you can order it by logging on the Educational Literature section at:  http://www.mbstone.com/literature/literature.htm. It's available in pay-per-download format and I consider it a cheap “insurance premium” to pay when there are thousands of $ involved! Not to mention the little and much needed support you'd be giving to the cause, your cause, since every single penny of the cost of the article will be used to support it.

Also, will you please read and e-sign our Statement of Purpose at: http://www.marblecleaning.org/purpose.htm? By spreading the word about this valuable site among your friends & family and the stone trades' people you've been dealing with you will be rendering everybody a valuable service!   

Also, do take advantage of the plethora of FREE Helpful Hints available at: http://www.mbstone.com/HH_promo/helpful_hints.htm. They're on the house!

Thank you.

Ciao and good luck,

Maurizio Bertoli

 

www.marblecleaning.org – The Only Consumers' Portal to the Stone Industry Establishment!