Question 1

Are natural green diamonds rare?

Accepted Answer

Yes. Strongly coloured natural green diamonds are among the rarest fancy colours, particularly when the green is evenly distributed through the stone rather than confined to the surface. Pure green in Fancy Intense or Fancy Vivid grades appears on the market only occasionally. Lighter greens and stones with yellow or grey modifiers are more available.

Question 2

What does undetermined colour origin mean?

Accepted Answer

Some green diamonds cannot be conclusively identified as natural or treated with current testing methods, because natural and laboratory irradiation create very similar defects. In these cases GIA and other laboratories may report the colour origin as undetermined. Such stones trade at a significant discount to green diamonds with a natural colour origin report.

Question 3

What are the brown spots on some green diamonds?

Accepted Answer

Small green or brown patches on the surface, often seen on the girdle, are known as radiation stains. They form where radiation-emitting minerals were in contact with the rough diamond, and green stains turn brown when heated. Cutters sometimes leave them as evidence of natural colour, but they are not proof on their own.

Question 4

Can green diamonds be lab-grown?

Accepted Answer

Yes. Lab-grown diamonds can be irradiated or otherwise treated to produce green colour, and they may look very similar to natural greens. Standard gemmological tests are not enough to separate them. A report from a major laboratory such as GIA confirms whether a diamond is natural or laboratory-grown and whether its colour is natural.

Natural Green Diamonds