Auburn hair is generally thought to be the most prized hair on Gor, but I myself generally prefer brunets. This is not to deny that blondes, suitably enslaved, and desperate to please, are not without interest. Blondes sometimes bring higher prices as their hair color is rarer, but once they are home, in the collar, they are, of course, no more than any other slave.
Renegades of Gor    Book 23    Pages 169 - 170
I walked slowly behind the Lady Florence. She knelt straight. "Your own hair," I said, "is a rich auburn."
"Yes," she said.
"Such hair," I said, "is very unusual."
"I am fond of my hair," she said.
"You might well be," I said. "Such hair would be the envy of many slave girls."
"You need not speak of it that way," she said.
"Did you know that auburn hair is highly prized in the slave markets?" I asked.
Fighting Slave of Gor    Book 14    Page 364