It's this rich, dark auburn-like fire when the light hits it at a certain angle.

I reached for it, and Tarran turned on me, his eyes like dark fire.

The dark fire is an evil and ancient enemy, older than the Earth.

They gleam with a dark inner fire like the fabric.

His eyes burned, as if lit with dark fire.

Only his eyes seemed alive, burning with a dark fire as he stared at her.

The dark fire will not avail you, flame of Udûn.

Eric could feel her strength, a dark fire joining his own power.

He caught her fingers and kissed them, and she met the dark fires of his eyes.

Merely white, bleached bones and eyes that burned with dark fire.