As far as I know, there's no written record of how it came about.. One theory is chocolates were bred from chocolate diamonds to breed more true. Another theory is different colors were mixed with chocolates to see what would come out. Take your pick. heh
I have chocolate diamonds. They are no more difficult than red cherries in my opinion.
BD were very sensative when I first bought them as a new import years ago. I lost maybe 2/3 in the first month. I was able to work with them to be more hardy- as other people have done too. When I sold off my stock, they were able to take what shrimpers in the US did to them. I think they may be pretty hardy in general by now, but I have no idea what the true breeding ratio is now. When I sold them off, they were maybe 20% true.
I recently bought some black roses. Hopefully they'll do well for me. Usually they only breed 5% or so true, but the person I bought them from claims to have done a higher percentage pf 10% or so. My aim to to create a much higher percentage.