Dear Pat:
First off, by your description you don't have Ubatuba at all. It sounds like Black Galaxy to me.
Neither one of those two “granites” can be technically sealed. So forget about the sealing thing.
Whatever stone you have, I can tell you that I smell rat big time. Let me explain something to you:
A stain – a real stain – is always darker than the stained material. If it is lighter, it's either a mark of corrosion created by an acid (etching), or a caustic mark created by a base (bleaching). There are no known exceptions to this rule. In the
However, neither Ubatuba nor Black Galaxy can get damaged by pH active substances. In other words, they don't etch.
So what's the deal?
I'm afraid that your stone has been maliciously doctored by the factory via the application of some sort of black “shoe-shine” to make a low-grading selection of Black Galaxy appear what it is not: black. And the “shoe-shine” is not giving thus revealing the real color of the stone underneath it and the fraud.
Unfortunately, it's a widespread criminal practice that finds harbor in the benevolent arms of the stone industry establishment.
But all this is only speculation at this point. (Although I would be extremely surprised if I'm wrong.)
What I suggest you to do is to send me a couple of pictures of your stone with the “stains”.
Only then will I know for sure and be able to tell you what your options are.
May I ask you now to please read and e-sign our Statement of Purpose at:
http://www.marblecleaning.org/purpose.htm?
Ciao and good luck,
Mauri
Article ID: 1104
Created On: Sun, Jan 27, 2008 at 11:32 AM
Last Updated On: Sun, Jan 27, 2008 at 12:00 AM
Authored by: Maurizio Bertoli [mail@mbstone.com]
Online URL: https://marblecleaning.org/knowledgebase/article.php?id=1104