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“Physical” bitcoin in Sydney auction

A Casascius coin, with a concealed private key to one bitcoin, is expected to fetch $100,000 in a Sydney auction this week.

The bitcoin network launched on 3 Jan, 2009, and it has been changing the way that we think of money. Fundamentally, we interact with its network by signing valid transactions using private keys and then broadcasting these. The transactions can be expressed as numbers, the keys can be expressed as numbers and so too can the receiving addresses. It’s all numbers!

For many, the nature of bitcoin is hard to grasp; It’s abstract. In an attempt to satisfy the desire for an embodiment of bitcoin, Utah-based Mike Caldwell launched Casascius coins in 2011. These were metal coins that bore a tamper-resistant hologram that concealed the private key for some bitcoin. Denominations for these ranged from 1 to 1000 bitcoin and the metal used from brass to gold. The production of these ceased in late 2013 when a branch of the Treasury advised Mike that he may be acting as an unlicensed money transmitter.

Because of their limited run and for their novelty and numismatic appeal, Casascius coins trade at a premium to the bitcoin that they contain. Even if the bitcoin has been redeemed, the Casascius coins are still valued.

In an auction running this week at the State Library of NSW and convened by Noble Numismatics, one of these rare and un-redeemed Casascius coins appears for sale. The estimated sale price is $100,000 and exceeds that expected for many coins of greater heritage. It is also nearly $70,000 above the current value of the 1 bitcoin that is concealed by the holographic seal.

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