Guinea negro

More likely to appear as the racial epithet "guinea nigger", common to portions of the northeastern South, and referring to any black of mixed race, especially to those with strikingly red hair, well into the mid-20th century. Common in east-central WVa. The melding of black and Nordic Caucasian bloodlines is likely to yield the trait, wherein the hair colors of pure black and pure blonde became red - the third pure hair color. It's quite specific to the blazing red hair - different, e.g., from "high yellow." (I heard it in my youth during the 40s and 50s, moved from the area, and have not since encountered it. Sadly, in that area at least, neither blacks nor whites would claim kinship with them and as often as not shunned them, so that they commonly chose to live in isolated communities among themselves.)

This is an uncomfortable exercise, as the usage is historic but most certainly deprecatory. Looking for common usages, etc., is simply in bad form. It existed, may yet be utilized, and is an insult.