Green diamonds are a rare gem color. Not more than a handful of natural green diamonds have been found. The two most notable are a 51 point dark green that sold for $69,000 per carat at Christie's in 1985 and a 3.02 carat apple green diamond sold for $568,000 per carat at Sotheby's in 1988.

Unlike other natural color diamonds, the cause of color in green diamonds is the result of natural irradiation in the earth. The problem with green diamonds, and the reason that a good one is so expensive, is the fact that the radiation usually does not affect the entire diamond. The diamond will appear green only in patches or on the surface. Color usually does not go very deep into the gem. Cutting and polishing usually removes most of the green color. The exception to this is the Dresden Green diamond. This 41 carat diamond is to green diamonds what the Hope is to blue diamonds. The Dresden is a truly exceptional green diamond with color throughout the gem and is on permanent display in Dresden Germany.

Through modern technology natural diamonds can be treated to become green. They are better priced than natural with stable color. If you buy a green diamond that is said to be natural, get a lab certificate. This is the only way to be sure you are not getting an enhanced green diamond.