Groovy Baby! Love it! I think if you are going to have a strong look like this, you have to go the whole hog to pull it off, otherwise it just looks like a bad take on a 'theme'; you nailed it, very well done!

How about some photos? What style? A mid-tone grey would look good with black sofas:

Marble are both non-porous thus it would cause etching and corrosion. Besides that, marble are high maintenance materials. Marble requires proper care and maintenance. Acid should never be used on marble as it shall loose its shine. Marble should be regularly polished over a period of time to give it a new look. If proper precautions are not taken the marble becomes yellowish in colour. Italian marble is usually very soft and prone to cracks. Proper resins have to be used to make the surface strong and solid and avoid further cracks. Proper sealants should be used in marble flooring as the marble is highly porous and prone to staining. It absorbs stains very quickly especially kitchen stains hence are not appropriate for kitchen counter tops. In the long run, wooden looking tiles (made of porcelain or ceramic) would be more practical. You can also consider marble looking quartz. You may check out the D & L series of iQuartz range. If you're based in Singapore you may call Stone Amperor in +65 87879029 for more information. If you're based in Malaysia you may contact AmpQuartz in +6017-7320149 for more information.

I have stained concrete floors and not only do I love them... but 95% of everyone that walks in the door goes goo goo over them... Well, there was that one guest that waited a half hour before asking "So, when you do you think you'll be able to afford carpet?" .... So, this isn't a great pic, but you can see that we mixed black in and that there's a greenish border... Looking back, I would have done a different color had I given it more thought because it's a lot of work to change stained concrete... but painted concrete can be painted over and over... By the way...The lower level of my house is 1500 sq ft and I vacuum those concrete floors, all of them, in less than 15 minutes... I was 2 x's a year and including stripping the old wax, it only takes me about three hours! This shine when it's done is SO worth the 3 hours ...