The coin, a gold Unite piece, has a currency worth of 20 shillings, said the British news agency SWNS, but it is expected to sell for roughly £1,500-£2,500 (about $1,800 to $3,000 in U.S. currency).

Liquidity. Another factor to consider when investing in gold is liquidity or the ease with which you can convert your investment into cash. In general, gold coins are more liquid than gold bars ...

Look for hallmarks. All authentic gold bars and coins have a hallmark stamp that indicates their purity. This stamp is a guarantee from a reputable manufacturer that the gold is 100% pure.