Casascius Coin

A Casascius Coin refers to physical bitcoins created by Mike Caldwell, a well-known figure in the early days of Bitcoin. These coins were essentially physical tokens that represented bitcoins and were intended as collectibles or as a means of gifting bitcoins in a tangible form.

The Casascius Coins were embedded with a private key underneath a holographic sticker, which could be redeemed by the owner to access the corresponding amount of bitcoins. The holographic sticker served as a tamper-evident seal to protect the integrity of the private key until it was peeled off for redemption.

These coins gained popularity among cryptocurrency enthusiasts and collectors due to their novelty and the ability to physically hold bitcoins. However, as the use of physical bitcoins posed security risks (since the private keys were exposed), and due to regulatory concerns, Mike Caldwell ceased production of Casascius Coins in 2013.

While the physical Casascius Coins are no longer produced, they remain sought after by collectors, and some are traded at significant premiums due to their historical significance within the cryptocurrency community.