Hey Magpie, mind sharing the region the mushroom was found and I will do some digging in the books.
I have similar purple Russula in Northern Indiana and I know I hunted down a species once.
Tricholoma sp
Strangely Green Giant Puffball
Gymnopilus Spectabilis
Hen of the Woods(Grifola frondosa)
Sporemageddon
Honey Mushrooms Cluster
Honey Mushrooms Cluster
Chicken of the Woods
I broke out my keys and there are a handful that fit the bill based off what I can gather from your photo, so I won't venture a guess. That white powder though is a common trait called "bloom" for some Russula. Cool stuff I have never seen that in Indiana before. Beautiful picture.
I can see why you gave up on Russula ID's. I kept coming across a wide range of colors for species. From purple to olive for the same species! Mushrooms are so strange and that is why they are fun.