I think I get what you're trying to ask, so I'll try to answer (Disclaimer: I'm a black man).
When it comes to the "properties" of "black" hair (and I'm talking stereotypical black hair here, hair similar to my own... if you're talking "types of hair on the heads of black people", that's much wider ranging), it's the texture. While a lot of people might think of coarse, curly hair as unrully, that's generally the opinion of people who don't know how to "manage"/do/style it. Managing it's growth tends to make you think of pretty ingenious ways of styling (cornrows, dreads, twists, afros, perms, etc.)
Now if you asking "what is it about black hair" in a "why" sense... Well opinions about black people and their hair, both positive and negative, internal and external opinion, have influenced black hairstyles throughout the ages... but that's a wikipedia article for another day.
When it comes to the "properties" of "black" hair (and I'm talking stereotypical black hair here, hair similar to my own... if you're talking "types of hair on the heads of black people", that's much wider ranging), it's the texture. While a lot of people might think of coarse, curly hair as unrully, that's generally the opinion of people who don't know how to "manage"/do/style it. Managing it's growth tends to make you think of pretty ingenious ways of styling (cornrows, dreads, twists, afros, perms, etc.)
Now if you asking "what is it about black hair" in a "why" sense... Well opinions about black people and their hair, both positive and negative, internal and external opinion, have influenced black hairstyles throughout the ages... but that's a wikipedia article for another day.