An 1879 US $5 green on black revenue stamp is expected to make around $85,000 in Robert A Siegel’s sale of the Grant Inman collection.

The stamp is printed on green silk paper, a measure undertaken to reduce the risk of counterfeiting.

Green paper variants of this issue were mentioned in literature of the 1870s.

This green paper variant wasn't known to exist until 1989 

However, there was no official record of one existing up until the late 1980s, leading many to believe they were a myth.

That changed in 1989, when the first example publicly came to light following the death of revenue expert Morton Dean Joyce – who had quietly owned one for many years.

Only 50 examples of this $5 on green paper variant were ever produced and only three are known to have survived.

This is the finest of those three and the only one not to have been repaired.

It last sold for $27,000 at Siegel in 2000, a sum it looks set to more than triple.

An unused 1898 1c Trans-Mississippi stamp overprinted "I.R./P.I.D. & SON" is expected to make around $30,000.

It’s one of four recorded examples of this variant, which was federally approved for the P I Daprix & Son river freight company, which operated along the Erie Canal in the early 20th century.

Another example overprinted “LHC” for the Chapman Steamboat Line (which also worked the Erie Canal) is valued at $12,500.

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