I believe these books were written in the 80's because i was reading them in the early to mid 90's. It is about a young woman who returns to an Island after many years because there has been a mysterious death (her female cousin i think...). Anyways, come to find out the orphaned daughter of her cousin is really her daughter and there is some old tension between the heroine and the daughter's father. I can see the cover, it is blue and i believe the word Island is in the title. She also wrote another book about turqoise necklace or earrings or something...