Irene is indirectly speaking about Clare here. In the previous chapter, Irene discusses Brian in her thoughts, and says that the main point of Brian's good looks is the richness and darkness of his skin. She identifies beauty as blackness, and Clare challenges that association in Irene's mind. Clare is repugnant to her, in more than just her looks, yet that mystifies and transfixes Irene in an unsettling way.