Most of us do not realize that diamonds come in different colors. The typical clear and sparkling diamond is what De Beers has marketed for 100 years or so…but if you want to own something truly unique consider this.
Diamonds have an extremely rigid lattice. They can be contaminated by very few impurities. Thus the clear, colorless appearance of those diamonds designated ‘gem quality’. Small amounts of impurities (about one per million of lattice atoms) will color a diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red! ‘Plastic deformation’ is the cause of color in some brown and perhaps pink and red diamonds.
In 2008, the Wittelsbach Diamond, a 35 carat blue diamond, once belonging to the King of Spain, fetched over US$ 24 million at a Christie’s auction.
“Black” diamonds are not truly black, but rather contain numerous dark inclusions.
White dwarf stars have a core of crystallized carbon and oxygen nuclei. The largest of these found in the universe so far, BPM 37093, is located 50 light-years away in the constellation Centaurus. The Harvard-Smithsonian Center for Astrophysics described the 2,500-mile (4,000 km)-wide stellar core as a diamond. It was referred to as Lucy, after the Beatles’ song “Lucy in the Sky With Diamonds”.
I was recently on ETSY, a site for handmade crafts including jewelry. I searched this huge site with about 250,000 virtual shops for ‘red diamonds‘. Click and take a look.
Gold ring with rough diamonds: 2 are yellow and 2 are red.
There are more red diamonds here.
Maidstonejewelry's Blog 
Awesome post on red & colored diamonds! Are you a gemologist? I have a little background in gems and greatly appreciate artists who tell interesting and informative stories about the materials they use in their designs :-} Look forward to more David!
Thanks Kaitlyn. I guess it is always about making it interesting.