“Eight-rock” is a term introduced in the “Patricia” section of the novel. It is described as coming from mining terminology, where eight-rock represents the deepest level of a coal mine. In the context of Ruby, Patricia uses “eight-rock” to refer to the extremely dark skin of the founding families of Ruby, which has been kept that way because they refuse to mix with outside populations. This refusal to interact with outsiders stems from the “Disallowing,” an event in Haven history where the founding families were denied shelter by the inhabitants of a town of light-skinned blacks. This event, alongside other kinds of colorist prejudice experienced by the citizens of Haven in the outside world, wounded the pride of the founding families such that they created a town where the opposite prejudice existed.
When we learn of the concept of the “eight-rock” families and the associated hierarchy, many events that have taken place earlier in the novel begin to take on different meanings. Earlier in the novel we read that Roger Best is suspected of being involved in the death of his wife. However, it turns out that at the time of Delia’s death Roger was at his mortuary school graduation, and that Delia died in childbirth because the men of Ruby refused to seek medical assistance for her in time: either because she was light-skinned, or because they did not want to ask for help from or bring a white person into town. We also read earlier in the novel that Menus lost his house because it was foreclosed. There is no explanation for the foreclosure, and Dovey, who now lives there as a second home closer to the town center, wonders why he was not allowed to keep it. In accordance with the “eight-rock” hierarchy, we learn that Menus was actually forced out of his house so that he could not marry the light-skinned girl he brought home from Virginia. Finally, the eight-rock hierarchy also explains why Billie Delia has been held in contempt her entire life for an innocent childhood act: as the granddaughter of Delia Best, she is especially susceptible to judgment from the eight-rock families.