Hello, I have read over most all of your Q&A and have not found much info on Green Onyx. I wish to re-do my shower and found an ad on an internet auction site for: FACTORY CUT GREEN ONYX MOSAICS Is there such a thing (green onyx stone) would it work in a shower and what is involved in the up-keep? Thank you! You have a wealth of information here, Dianna in Seattle

 

Dear Dianna:

True Onyx is silicon dioxide and is a cryptocrystalline form of quartz and only physically differs from Agate. It is 7 in the Mhos scale of hardness (as hard as the average granite) and is mostly used in the jewelry trade.

 

The more down to earth onyx that you can find at your local stone dealer is in fact a form of travertine and is a highly calcareous rock (mostly in its aragonite version) very sensitive to acidic substances and with hardness on the 3 to 3.5 range. In other words, they are two different animals altogether, carrying the same name just because for certain aspects they look similar... Well, kinda. (Truth to be said, some call it more appropriately, marble-onyx.) Would I use marble-onyx in my own shower stall? Not if they'd pay me to get it.
But now there's this green-onyx that you're reporting about and that I don't know the first thing about… Will that be okay for your project? I have not a clue!

Of course, the merchants selling it probably know even less then nothing about it, but what can I tell you? Welcome to the stone industry!

 

In conclusion, despite the high appreciation you seem to have about my (alleged) expertise, I'm afraid that I'll have to let you down on this occasion… Sorry.

To make sure, if the industry were at least a bit regulated this problem would not exist, but there's only one hope for consumers and consumers-to-be-of-stone to see to it that what they're sold is disclosed in all of its characteristics; and that hope carries one name: marblecleaning.org. But we can't do it by ourselves; we need the support of as many consumers as possible to make it happen.

So, may I ask you to please read and e-sign our Statement of Purpose at: http://www.marblecleaning.org/purpose.htm?

Ciao and good luck,

Maurizio Bertoli

 

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