I'm trying to work out a taxonomy of the various views someone might hold regarding the nature of racial groups. One of the views, sometimes called racial realism, takes races to be natural kinds something like species in biology. On this view, their basis lies in biological facts completely independently of any historical origins of racial groups, social facts about how we treat each other, or lingustic facts about how we use racial language. I'm not interested for the moment in whether this view is true. I'm interested in various forms it might take.
One element of this sort of view that virtually all the scholars who work in this area ignore is that the natural kinds of race may not involve anything particularly insidious. This view could hold that racial groupings are based on skin color, bone structure, hair type, and virtually nothing else. As long as its proponents insist that such characteristics would be enough to constitute a natural kind, then it's a realist view. This isn't the most historically influential racial realist view. That view holds that certain intellectual, moral, and probably several other characteristics must follow from being part of a certain racial group. But it is a kind of racial realism.
What I've been puzzling through for the last two or three hours is what some people mean by calling this sort of view "racial essentialism". First off, I'm not sure if that term is supposed to apply to the milder kind of racial realism that most people who work in this area ignore. Second, I'm not sure what it means even if it's just supposed to apply to the more extreme view that was used for so long (and still is in some quarters) to legitimate white supremacism and other forms of racism.