They used to be separate, but then people just mixed them together. I never found any in the US with a long search years back. I did find some people who had "mahogany" charcoals, which basically were just really, really red ebonies from what I could tell.
As for not being popular or what not, they don't have a pelt value because they are a "matte finish" type of chin. Anyone who would work with them would be doing it for the hobbyist value and since they would have to be imported, I think most people haven't bothered.
Claire's are beautiful. I'm glad the people in the UK are working with them!