Elsa, yes, diamond dusting, when it occurs on daylilies, seems to be much more pronounced than it is on irises. At least, that has been my observation.
I have NAVY BLUES, but curiously enough have not noticed any diamond dusting on it. I just repotted it this last summer, so I'll be sure to take a close look at it when it is next in bloom.
I am also very much in love with metallic edges on flowers. Not "gold" (as in the color gold), but gold metallic or gold gilt... also silver metallic, and any other metallic. They don't need to be WIDE edges (actually, I think in daylilies the breeders have gone way too far with very wide double and triple edges, to the point of grossness
), but they need to be consistent all along the outline of the petal or sepal (in irises, that would be standards or falls). A nice thick (not hair-thin, but not grossly wide either) metallic wire rim is a lovely finishing touch to a flower, I think.
In that vein, I have NATURALLY SWEET, which supposedly has a "very thin" copper gold edge. I've seen it bloom all of once (it's neglected in the side yard in a one gallon pot) and I don't really recall if it does, so I should probably up-pot it and move it somewhere, where I can better evaluate it.
So many irises, so little room (or energy).