The seller told her it was a rough brown diamond. Runsdorf, in disbelief, said she wanted it verified by the Gemological Institute of America. Sure enough, it came back as a certified 65-carat ...

Brown diamonds are caused by the crystal becoming deformed ... Blue diamonds only need a tiny amount of boron to produce colour, but they are much rarer than yellow ones. A green diamond means it has ...

making them appear green. Whatever the reason, diamonds come in a rainbow of bright, beautiful colors, and then there are brown diamonds. For centuries, brown diamonds were cheap. They were ...