Give them an Albert - give them some time and space.

Swissmint has announced that the world's smallest commemorative coin is a tiny Swiss gold coin featuring Albert Einstein sticking his tongue out. This coin has a face value of a quarter of a Swiss franc and measures just 2.96 millimeters in diameter, weighing 0.063 grams. Only 999 of these coins were made and they all sold out quickly. The reverse side displays the coin's value, the Swiss cross, and the word "Helvetia," the Latin name for Switzerland. To see the coin's details, special packaging with magnifying lenses and light is required. Switzerland also holds the record for the world's oldest coin still in circulation, a 10-centime coin minted in 1879, featuring a woman's profile on one side and a face value surrounded by oak leaves on the other. This coin has been in use for over 140 years and is recognized by Guinness World Records as the world's oldest circulating coin.

Source: Swiss strike gold with world's smallest commemorative coin (phys.org)