The short answer to this question is no.  In a few rare cases, there are priceless natural fancy colored diamonds, like the blue Hope Diamond (right) at the Smithsonian in Washington, DC.  But in 35 years in the diamond business, I can count on one hand all of the fancy natural colored diamonds that I have ever seen, and not one of them have been bought or sold by me.  If you have a natural blue, pink or yellow diamond that is certified "fancy color" by the GIA (Gemological Institute of America), I believe you would know it and it would be worthy of a collector.  You should go to the finest retail jeweler in town that has a flawless reputation and have their gemologist look at your diamond.  It might cost you a couple of hundred dollars to have it certified, but your investment in testing would pay off in the long run.

Chances are, you have a yellow diamond that is naturally found in the ground or that the diamond has been enhanced by some sort of chemical, radiation or heat.  Many times diamonds have been enhanced by giving a lifeless brown looking diamond some color by subjecting it to radiation.  Don't worry, the diamond is not radioactive and there are no know dangers to wearing enhanced diamonds.  The enhancements are just that...they make a bland ugly diamond into a beautiful piece of jewelry.

Look at this diamond cross (left) and you'll see a row of tiny white diamonds that outline the cross and some enhanced blue diamonds that are a little larger, in the center clusters within the outline of the cross.  This is a pretty piece of jewelry, but it was mass produced and sold as a regular consumer item.  The blue diamonds might be more expensive than the white diamonds, simply because they had to go through an additional process (enhancement) before they could be used.  They most likely started out life as brown diamonds and then they were enhanced to a blue color.

Bottom line...enhanced diamonds or even natural brown (champagne) or yellow diamonds are not worth as much as a colorless or near colorless diamonds.