More pictures of dark grey...

Could I use this as the sink? Would it look good with the porcelain tiles?

Yes, you could use that as the sink, but keep it simple. The all black powder room above shows that with only the sink as contrast.

Have you already searched Houzz photos for 'gray red powder room'? Here's what I found: [houzz=]

I want to use some red how can I use red marble in the sink.?

Do you mean an actual red sink? Or a red marble countertop?

Red marble countertop.

If you search Houzz photos using the search term 'red countertop' you will find 107,177 photos! Perhaps you could try this to find the one you like?

Is it true that when decorating a room you should use 60% of a dominant colour , 30% of another one to create a contrast and 10% to use in accessories? Should I follow this theory?

Yes, that's the general rule of thumb. But I think it sounds easier than it is. To me, it's what pleases the eye!

That is if you are using different colours - if you want drama you bend the rules a bit - and a powder room allows you to bend the rules a lot!

I want to use light grey, dark grey, beige and red because I think they r beautiful colors, like the ones in the photos. However, I find it really difficult to combine them all together. Is there a software that allows you to see your powder room before in order to avoid making mistakes? Thanks

Can you post a pic or two of the actual room?

The room has just been built. It s a 54sq feet rectangular room.

What do u guys think about this powder room?

Carolyn a countertop would look like sth like this?

I don't think I'd want 3 different marbles in one room. Two marbles with veining are fine. Three is one too many. So you could settle on two marbles and a solid color countertop, or match the countertop to one of the marbles on the floor.

Thanks Carolyn! Could I use for example beige and red marble on the floor and on the countertop as well? And use light grey porcelain on the wall and white paint on the other wall? Thanks

I think you are trying to mix too many things in this powder room. It could possibly work but it's too iffy for me to approve it without seeing the products and the space or plan in person. This is an instance when I think you need to hire an interior designer to help you achieve the look you want in order to avoid making an expensive mistake

HI
Here are some pictures of the powder room. But still don t know what colour to use for countertop marble...

I used dark grey and light grey only...

Can you please provide us with photos that are clearer?

These ones

Our recycled glass countertop would look great because it is a more neutral grey and allows for a lot of decorative opportunities!

What you have so far is lovely and sophisticated. I believe that the black marble with white veining would be perfect with your tile.

Then to bring in some red, consider a large piece of art.

I want to use a glass block little wall as a separation between the countertop and the WC, should it be a neutral color?

The black marble with white tile should match the opposite black wall?

I was not aware of a black wall. And this is the first I've heard about a glass block wall also! Instead of a glass block wall between the vanity and the WC, I would use a frosted glass panel.

Well this is the black porcelain tile wall

I found this example of glass brick wall in houzz.com. http://houzz.com/photos/1110163

This too http://houzz.com/photos/796271

http://houzz.com/photos/796271

I would prefer a glass panel which I think looks better and takes up less space. It would be similar to the one below, but frosted glass.

Regarding the black wall, I understand now that it was the gray tile wall you meant . It should be fine with the black countertop.

What options in colours do u think I have for the marble countertop?