From the Internet:
"Where did the term "white elephant" originate? As the story goes, it had something to do with the great showman, P.T. Barnum. Barnum, always looking for a new source of entertainment to bring in the crowds, was earnestly seeking a new attraction when his prize attraction, Jumbo the Elephant, was killed by a train.
Barnum needed a replacement and not just any replacement would do. Barnum decided that an albino elephant would do the trick and bring the masses back with their money. Barnum found a "white" elephant, but the problem was that most people who had paid good money to see the animal thought its color was closer to yellow than to white. Thus, the term "white elephant" represents something with a value exaggerated beyond its true worth. "

Story I allus heard was the white elephant was highly valued by Siamese(?) society and to be given one was a great honor, but the visiting British found it to be more of a burden than an honor when faced with the problem of what to do with any elephants so generously imposed upon them.

Yesterday's word had this derivation from Wordsmith:

"From the King of Siam's reputed practice of awarding a white elephant to a courtier who had fallen out of favor. A white elephant was considered sacred and couldn't be put to work, so the upkeep of the animal would ruin its owner."

Ed.: but I reckon all three of these stories are true, proving that a white elephant is highly undesirable.

Dear dxb: But I'll bet Barnum made money from his white elephant, even if it was jaundiced. And I still think ir likely that he was responsible for "white elepnant" becoming widely known.

Did these white (or yellowish) elephants have pink eyes? Do all albinos have pink eyes? I don't think so. It seems recently I saw something I've forgotten that was white--and white was not typical of this species--but it did not have pink eyes. So I wondered whether it could have been a true albino. If I remember what it was that I saw, I'll add its name here...