Among the highlights in Cherrystone's small but gem-packed sale - including arguably the world's most famous stamp, the Inverted Jenny - is this exceptional Russian rarity.
Dated to 1883-88, this pair of 1k orange invert stamps ('invert' meaning its design was accidently printed back to front) comprises two of just six known examples in the world.
According to Cherrystone's lot notes, these singles were originally a horizontal pair and later rejoined. They were later cancelled in the Ukraine, as evidenced by the applied handstamp which reads "Izum, prov.Kharkov".
The handstamp is dated "10 Feb 1886". Each of the stamps boasts a bright colour and are well-centered.
In terms of condition, at the right-hand stamp's top right corner is a light diagonal crease ending with a small tear. The left-hand stamp, meanwhile, is described as "very fine" in Cherrystone's description.
Despite the slight wear and tear, this stamp pair's rarity is key to its value - as well as exceptional provenance, having formerly been part of the renowned Mikulski and Fabergé (of ornamental eggs fame) collections.
Also among this pair's previous owners is Bill Gross, the billionaire "bond king" and famous collector whose previous acquisitions included the World Record-priced Inverted Jenny block of four.
Billed by Cherrystone as "one of the most important groundwork inverted rarities," this rare Russian pair is expected to bring $75,000, if not more, when bidding closes on December 16.