I'd expect a thread this ignorant from a white person, but as a Black person you should be ashamed that you aren't aware of your own roots.
Eurocentric ideology has tried to portray Blacks as this monolithic race of people with no diversity, when in fact science has shown that Africa has the highest genetic variation out of any continent (as the origin of man). People tend ignore that Blacks have their own genetic variation of different skintones, features, and hair types without European admixture.
These are Igbo women from Nigeria. They are pure Black.
Beyonce and Rihanna may have some European heritage, but that doesn't mean they "don't look Black", because Black is a very diverse identity.