On June 6, 2019, the Austrian Post issued the world's first crypto stamps, designated 1.0, with a symbolic unicorn engraved. The 5 stamps had a face value of €6.90 each. The total circulation was 150.000 stamps. Each stamp was assigned a digital equivalent in the Ethereum blockchain with an additional non-fungible token (NFT) making each stamp “unique”. The left part of each stamp could be used as a postage stamp, while the right, detachable part contained the token and access codes to an Ethereum wallet that had to be scratched free.

The postage stamps themselves look all the same, but each stamp is assigned one of 5 colors for their digital equivalent: black, green, blue, yellow or red. The particular color of a stamp could be retrieved via the QR code or token ID. The print runs for the respective stamps were 78.500 (black), 40.000 (green), 20.000 (blue), 10.000 (yellow) and 1.500 (red). Therefore when one bought the stamp(s) for €6.90 each, one didn't yet know which of the colors was assigned.

In terms of collecting the stamps there seems to be an additional aspect. While each stamp is unique through the assignment of a singular NFT code, the NFT codes themselves seem to also be a categorizing differentiator for collectors of such stamps. The code has between 4 and 6 digits with 4 digits being the most limited. Thus the red color with 4 digits is the rarest. Also a distinguishing feature are the letters of the code in them being only capital or small for distinction. How much such differences are "collect-worthy" is certainly a matter of a collector's preferences.

The debates of whether crypto stamps are collect-worthy altogether continues on. While the more conservative community of stamp collector's are more or less opposed to such stamps, it is combining the classical stamps with the digital world. And the crypto stamps are finding their buyers, not all crypto stamps with the same enthusiasm though. And while those stamps in their physical form would rarely be used for postage, also due to their usually high franking value, they are valid postage stamps.

Blockchain

A database which is distributed over many computers. Each record in the database is called a "block". Each block has a unique identifier (hash value). Each block also knows the unique identifier of the preceding and the succeeding block. Therefore the blocks are organized like a chain hence "blockchain". If someone would try to tamper with a unique identifier of a block, the blockchain would be broken.

Wallet

A wallet is to be understood like a physical wallet just in the digital world. The wallet contains assets which belong to the owner of the wallet. This can be digital coins like Bitcoins, ETHs or other digital currencies. Or it can be a digital stamp. And the content can be bought or sold and would then come into one's wallet or leave one's wallet to go to another wallet.

NFT

A non-fungible token (NFT) is a unique identifier for a digital asset (like a digital stamp). In the case here with the 150.000 stamps printed, there are 150.000 digital stamp equivalents each of which has its own NFT, therefore each of the 150.000 (digital) stamps is unique in its own right.