This trilogy by Anne Bishop contains Daughter of the Blood, Heir to the Shadows, and Queen of the Darkness. The trilogy can be purchased as either seperate paperbacks or a combination paperback. (if anyone has seen them in hard back, please /msg me becuase I have been searching for them.) There is also a companion book, The Invisible Ring set in the same world but not part of the trilogy.

Some Background:

The Jewels:
Their are thirteen jewels, all different colors ranging from white to black. Each jewel has a different range of strength. Darker jewels are more powerful than lighter ones. Opal is the dividing line between lighter and darker jewels because it can be either. When a Blood child is seven years old, they have their birthright ceremony. If they are strong enough to wear a jewel, it just appears on the alter after the ceremony. An uncut jewel is large enough to make a ring, a pendant for a necklace, and provide chips that are useful for many spells. When a person is ready, usually in their late teens or early twenties, they make the offering to the darkness. The offering takes from sunset to sunrise and a person can decend a maximum of three ranks from their birthright. (i.e. birthright white could decend to rose) If they are strong enough to decend, a second jewel appears. Wearing her jewels or channeling any power through her body durring her moon time causes a female physical pain.

Virgin Night
It is hard to break a male but a Blood female's power hinges on her virgin night. If the breaking of her hymen is done gently by one who cares for her well being, she steps away from the bed with only her hymen broken. If the breaking is done with anger or the female is frightened, she can be cut off from her own power as she breaks her inner web trying to escape the pain. If she goes too far, she can shatter her mind as well as cut herself off from the strength of her jewels. A male doesn't have to have the dominant strength to break a female on that night.

The realms:
Terreille is called the realm of light. It is the farthest realm from the Darkness and one of the two living realms. Terreille's Blood has "whored the old ways". The strong Queens are broken on their virgin night and never grow strong enough to heal the harm being done to the land. Strong males are ringed with the ring of obedience to prevent them from becoming a threat and to force them to serve. The landens (non-Blood) live in constant fear of the whims of the Blood. Very few people in Terreille believe that the other two realms exist.

Kaeleer is the darker stronger of the two living realms. It is called the shadow realm. It's queens still protect the land and the dance between the genders is how it should be. The men in a Queen's inner circle serve and protect. The women respect a male's strength and nurture it. The land is healthy and the relationship between Blood and landens is not so strained.

Hell is the dark realm. Hell is a cold, forever twilight realm where the demondead come to say their goodbyes to life before finally fading away into the darkness. It's High Lord is Saetan Daemon SaDiablo. He is usually a benevolent ruler of the demondead who reside in Hell.

The Books

Daughter of the Blood tells the story of Jaenelle's early childhood. Wearing the Black Jewel as her birthright makes her strange and powerful but she is still just a little girl vulnerable to her family and wanting everyone's approval. She is still open to influence and corruption. Everyone wants to control her power or destroy it for good.

Heir to the Shadows takes us through Jaenelle's adventures in Kaeleer durring her adolecence. Saetan guides and protects her. Her ordeals in Daughter of the Blood have left her mind fragile. She is haunted by the battles fought over her. She still seeks approval and love from Saetan but she is wary of people now. When her memories return and her magic matures, Kaeleer is forced to come to terms with it's new ruler.

Queen of the Darkness Jaenelle reigns as the Queen of Ebon Askavi. The time has come to rid the Blood of the creeping taint that is destroying it. She will do whatever is necessary to protect her people, even make the ultimate sacrifice.