You are not going to carry a diamond it self are you ?
No, you are going to put it on a neck less or a bracelet or a ring, you are going to put your diamond on a "surface", on something. He is not a diamond dealer, as i see he sales rings...
What is the MAIN surface you are going to set over a diamond ? gold, white or gold. I think 80percent of jewelery is made with the actual yellow gold. If not it is going to be white gold, platinum... and any other things... but most likely gold.
Which brings us to a website matching to a dark brown gold color.
for example :
http://www.maty.com/homepage.aspxhttp://www.philippetournaire.com/Of course his color is NOT bad at all and can work good, but i think something calm would look better.