How do you deal with an African American coworker who is extremely prejudiced against any person not of "color" & is dedicated to getting the 2 Anglos where I work fired?

I am in my first month at a new job. I’ve always treated this person with respect & kindness & have never said anything to her that could be misconstrued as racist or offensive unless you consider “Good morning and How are you doing today” racist. This person hates white people & has told me that all white people are descended from slave owners who did terrible things to her ancestors. I explained that I come from Cherokee/Chocktaw, French-English descendants who were not slave owners because I’ve researched my family back to the 600’s. She told me all white people have different races mixed in and my Native American heritage didn’t mean anything and that all white people did own slaves. Then she turned me into Human Resources for making racist comments and tried to have me fired. She also tried to start a fight with the only other white person at work and tried to have her fired as well. This is getting awkward – how do I handle this?