The Ruby Knight (Book Two of The Elenium)

The Elenium series, which began in Diamond Throne, continues against a background of magic and adventure.
 
Ehlana, Queen of Elenia, had been poisoned. A deep enchantment sustained her life, but only while the Knights aiding it still lived—and already they were dying, one each month.

Then Sparhawk, Knight and Queen’s Champion, learned that the cure for the poison was the Bhellion, the great jewel lost when Sarak of Thalesia had died in battle, five hundred years before.

Sparhawk and his companions set forth to find King Sarak’s grave by raising ghosts of those who had perished in that ancient battle. The Seeker, an insectile monster spawned of the evil God Azash, hounded their every step. Still Sparkawk pressed on, driven by desperate need. They had to find Bhellion before his queen could perish. They must not fail!

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....