The Elenium by David Eddings (Complete Series: Books 1-3)
The 3-book set of mass market paperback novels includes the below titles:
The Diamond Throne (ISBN 9780345367693): Sparhawk, Pandion Knight, and Queen’s Champion have returned to Elenia after ten years of exile, only to find young Queen Ehlanda trapped in a block of ensorcelled crystal. As Sparhawk sets out to find a cure for Ehlana, he discovers that only he can defeat the evil plots that threaten her rule….
The Ruby Night (ISBN 9780345373526): Ehlanda, Queen of Elenia, has been poisoned. A deep enchantment sustains her life, but it will end soon. Then Sparhawk, Knight of the Queen’s Champion, learns where to get to cure for the poison. He and his companions set forth on a dangerous quest to find the antidote before the queen should perish and the peace ends….
The Sapphire Rose (ISBN 9780345374721): Finally the knight Sparhawk had come to possess Bhellion, the legendary jewel of magic. With it, he frees Queen Ehalana from the crystalline cocoon that preserves her life, but Bhellion carries dangers of its own. And now Sparkhawk is being stalked by a dark lurking menace that is only the beginning of his troubles….