Thinking about it I guess it actually was fungible. On a couple different levels. So a FT
From the New York Post:
An 1856 British colonial stamp once owned by the eccentric millionaire and convicted murderer John du Pont — and which broke records in four auctions — is going under the hammer again in the Big Apple.
The British Guiana One-Cent Magenta, described as the most famous and valuable stamp in the world, is expected to sell for up to $15 million – more than a billion times its original value – on June 8, The Guardian reported.
“It is the Mona Lisa of philately,” philatelic expert David Beech told the news outlet. “It is the one stamp that every philatelist and every collector would have heard about and seen an illustration of.”....
....MORE, including pics.
I think those guys just like saying "philately"