0.25 franc - Smallest gold coin in the world

Image of 0.25 franc coin - Smallest gold coin in the world | Switzerland 2020.  The Gold coin is of Proof quality.
With determination, patience and inventiveness, Albert Einstein revolutionised the world view of physics with the formula E=mc² in 1905. Swissmint tried to apply the same qualities to the creation of "the smallest gold coin in the world", by using absolute precision and technical sophistication to achieve a world record in coin minting. The unique result is a machine-minted gold coin with a diameter of 2.96mm weighing only 0.063g (1/500 ounce). The obverse of the smallest gold coin in the world features the famous image of Albert Einstein sticking out his tongue, and the year date 2020. The reverse shows the nominal value of 1/4 franc together with the inscription "Helvetia" and the Swiss cross, supplemented by the alloy mark "AU 999.9" and the weight (1/500 ounce). Because neither image on the minted sides can be discerned with the naked eye, Swissmint has commissioned special packaging complete with magnifying lenses and light, ensuring that you can examine the smallest gold coin while still keeping it safely stored. This edition is limited to just 999 units.