Produced by the University of Glasgow, it is invisible to the naked eye.
Its school of engineering drew up the design to highlight its "world-leading" nanotechnology expertise.
A total of 8,276 cards could be placed on a single stamp.
Professor David Cumming and Dr Qin Chen etched the Christmas tree image on a tiny piece of glass.
Prof Cumming said: "Our nanotechnology is among the best in the world but sometimes explaining to the public what the technology is capable of can be a bit tricky.
"We decided producing this Christmas card was a simple way to show just how accurate our technology is.
"The process to manufacture the card only took 30 minutes. It was very straightforward to produce as the process is highly repeatable - the design of the card took far longer than the production.
"The card is 200 micro-metres wide by 290 (m] tall. To put that into some sort of perspective, a micro-metre is a millionth of a metre; a human hair is about 100 (m].
"You could fit over half a million on a standard A5 Christmas card - but signing them would be a bit of a challenge."