Amber is a unique color in the Norwegian Forest cats and creates a color change in the coat as the cat ages. In the simplest explanation a cat with amber coloring is genetically black but the black color fades from the coat to a golden or amber color. The color change can be quite stunning.  The amber cats can be any of the (tabby patterns) Agouti or Non-Agouti (without a tabby pattern). They can be solid or have any amount of white.  Here is where the fun comes in; a non-agouti cat (not tabby pattern) can appear as a tabby due to "ghost markings" come out with the color change. My personal favorite is the non-agouti with the dark nose and face markings. 

To produce the amber color both parents must carry the amber gene. We took special care to select well-bred amber cats to add to our cattery. Choosing an amber female and male who is an amber carrier. We originally planned to have a focus on the amber colored cats in our cattery. While we do still have Judy a black silver amber and Pharaoh a black silver tabby and amber carrier, we will not be focusing on this color at the cattery at this time. Our goal remains to produce the best Norwegian Forest cats we can to preserve and further the breed.

In the cat fancy as this nontraditional option emerged, people either really like the color or dislike it. Within the genetic research on the gene that causes amber the jury is still out on what other changes can happen with that gene mutation.  You can find some additional reading on the color at The Little Carnivore website and  "Norwegian Forest Cats in Amber" written by Dr Marc Peterschmitt.