A rare red Spanish Colonial handstamp on a letter from Florida to Havana, Cuba has so far attracted bids of up to $14,000 in the auction of the Floyd E Risvold collection of rare stamps, books and documents in New York.

Datelined "San Augustin de la Florida 28 Jan 1785", the letter was sent unpaid, and two silver reales were charged on arrival.

The piece is regarded as the greatest Florida cover in existence, as it is both the only known postmark from Spanish Florida, and the earliest reported town marking from any former Spanish colony in present day US territory.

Stampless cover of Spanish colonial Florida

$14,000 is a healthy bid from interested parties on the internet, but it is thought that the cover could easily achieve even more than this before the end of the live auction.

The slightly worm-eaten cover comes with a photocopy of a letter found in the Spanish archives dated 21 December, 1784. The letter was actually sent by a postmaster, and the contents provide confirmation that the handstamp was applied in Florida on leaving, not in Cuba on its arrival.

The live auction of the collection, which includes covers from the Nugget Express and Snowshoe Express amongst many other philatelic rarities, has now begun, and will conclude on Friday.