Series 1 1,000 BTC 2011 ‘Prototype’ Gold Coin
This rarest and most valuable of all Casascius coins is also the first gold coin produced by Casascius, and was meant to be only a prototype. Mr. Caldwell’s did however sell it to a buyer he met at a conference, who was unwillin to wait for a new coin to be minted. The pictured coin was sold by the original buyer for 1,000,000 USD (paid as a mix of USD, BTC, LTC, and gold) in November 2013, the highest price ever paid for a Bitcoin related item. If the value of 1 BTC were ever to approach 10,000 USD, this coin could potentially become the most valuable coin ever sold.