Austria’s newspaper stamps, known as the Mercury stamps, first
appeared in 1851. They were the first newspaper stamps issued in the
Czech territory. The stamps, designed by engraver Josef Axmann, were
very small and were not denominated, the colour indicating the value.
They depicted a profile of the Greek messenger god Hermes, known in Rome
as Mercury, framed with the text (clockwise from top to bottom)
“ZEITUNGS” – “POST” – “STÄMPEL” – “K.K., and a rose in each corner of
the frame. The stamps mainly differ in colour. The most common blue
stamps were stuck directly to newspapers, which are quite often
preserved. The yellow and pink stamps were used for larger numbers of
copies. The Red Mercury, also known as the Scarlet Mercury,
is the rarest of the Mercury stamps. They were glued to tapes used to
frank a bundle of 10 newspapers. The tapes were torn and discarded after
delivery, which makes the Red Mercury stamps one of the top ten most expensive stamps in the world.
Source: https://www.ceskaposta.cz/en/
Stamp:
Stamp on Stamp - "The Red Mercury Stamp" (from a set of 2) - Issued: 23-09-2020
Many thanks to Vladimir!