My first question is did he use mastic or thinset to adhere them to the walls? Mastic would come "premixed" in a resealable plastic tub. Thinset would be dry powder in a bag, add water.

Photos?

I appreciate your help, thank you. I believe that he used thinset, since I've seen several paper bags appr. 14 x 20 in. and it was a light gray paste, which was generously applied to the wall underneath mosaic. In addition, he used white grout, which does not look nice at all. Is it possible to apply colored grout now on the top or it will ruin everything taking into account porous structure of onyx (it is polished).
Nickol

Is it possible that Enhancer and Seal For Natural Stone caused these wet-like stains, which are not all-over the bathroom, but mostly accumulated on one of the walls?
Nickol

photos?

Looking just at the enhancer/sealer possibilities, did your contractor leave any of the enhancer/sealer with you? or, go out and get some. then, on a NON-wet-looking tile but NEAR the wet-looking tile, apply the enhancer/sealer to maybe one tile or so depending on size of tile. after it dries (the time it says to dry on the enhancer/sealer), does it look like the wet areas or the dry?

I put tumbled onyx 4x4 honey and tumbled onyx 1x2 multi mosaic in our shower (and backsplash on vanity and kitchen too for that matter) and I liked the wet look better. I used the 501 enhancer/sealer before installation and some of the tiles did look different depending on whether they were darker or lighter stone naturally. However, looking at the tiles as a whole, they did not at all look like some were wet and some were dry. maybe the test above will help and maybe answering mongo's and pharaoh's questions will help determine the answer.

hth

This is a link to the photo. I am very disappointed with the result of the job made by the contractor. In addition, there are areas where the tile man (he did this following the instructions of the contractor) tried to repair the uneven surfaces between the layers of the mosaic. In these areas he applied generously silicone. I am desperately trying to find out the way to repair all this disaster. Please advise what can I do. If any...
http://home-and-garden.webshots.com/photo/2348539830059557672VDjsEm
Nickol

I'm not sure I can see what you're referring to in your photos. it looks really pretty, actually! I'm sure you can see it in real life though... maybe you can take closer pics of perhaps circle the area on the photo so we can see what you are talking about ?

I believe white thinset instead of gray should be used with onyx since it is translucent and the gray alters the color--at least that is what I have read. I'm sure the experts will weigh in on this.

Hi, thank you for the response. I posted two more photos on the webshots. Maybe this will give more clear picture what I cal "wet-like". These are blurred areas located mostly in the center of the pictures.
In the bathroom I have polished onyx mosaic, but after it's been processed with Enhancer and Seal there is no shine anymore, everything is dull. It is practically impossible to clean the surface to make it shine again, I can do this with great difficulty with paper towel just in little areas. I read couple of days ago that stone should be cleaned thoroughly before sealing, but I know for sure that this was not done. I was at home and the walls were dirty, and they applied seal in 10 minutes. Can I repair this to return shining of the polished onyx?
http://home-and-garden.webshots.com/photo/2348539830059557672VDjsEm
Thanks again,
Desperate Nickol