The ruby was the size of a small egg. It was cut and polished until
its burnished sides threatened to obscure the inner fires with their
glimmerings. But deep inside the jewel was a core of flame that would
never be extinguished. That flame looked purple.
Thor wondered. Purple heart of red ruby. Suppose Aava had imprisoned a
jot of his immortal fire inside the ruby, as he had with the androids!
He turned it over. There was a rocking instant of vertigo, of pitch
blackness and cold.
The meadowlands were gone. He was standing on a rocky escarpment that
brooded over a small valley. And set in the middle of the valley, like
a vision from an Arabic nightmare, was a city of elfin loveliness.
Towers pointed slender spires to the sky, and hemispheric domes glowed
softly in pale moonlight.
"The City of Aava," murmured Thor. "This is the place they sang the
song to the urn, the city the Discoverer showed me."
His fingers tightened on the ruby. He turned it carefully.
He was back with Slag.
The dwarf-man was whining, and looking around him like a scared dog
until he saw Thor looming massive in the fire-flames. He grinned and
came close, shaking his club.
"You go where Karola went? Where the men come from?"
"Yes. It's a different world, Slag, but the same. I've a feeling this
ruby with the green fire in it is some sort of passport, or key, that
unlocks the path into Aava's realm. It's a physical manifestation of a
geometry Euclid never got around to. Dimensional worlds."