What you might do is cross your seedling with something like 'Ed Brown' (presuming it has some degree of diamond dusting) or 'Fiji' (as suggested above). I imagine the color of the resulting F1 seedlings will be paler than your current seedling, but then you could either cross those F1 seedlings among themselves, and select for color and diamond dusting, or else (if you have an F1 with good diamond dusting) cross that back to the original parent seedling to try to recapture the color.
In any event, if you want to keep that lovely color, then you are either going to have to find something similar in color AND diamond dusted to cross your seedling with (good luck with that, I haven't a clue, maybe someone else might jump in here) or else resign yourself to a couple generations of work. That is imho... advice from the more experienced hybridizers on board is welcome and will probably be more useful to you.
(Fred? Anyone?)
