The term “half sovereign value” refers to the market price of a half sovereign coin, either in terms of its collectible value or as bouillon by commodities traders. Half sovereign coins contain 22-Karat or 92 percent pure crown gold alloy, equivalent to 0.18 troy ounces or 3.66 grams of gold.
Half sovereign coins have a face value of half that of a sovereign equivalent to one-half pound sterling, 10 shillings or 120 old pence. Coins minted after 1817 contain 92 percent pure crown gold alloy that commodities traders trade on the gold market as bullion at market prices.
Since Great Britain stopped valuing money according to the gold standard, production of the half sovereign stopped, so the coin often has a collectible value that substantially exceeds its face value. The price of gold also contributes to the higher value. The British mint periodically strikes limited quantities of commemorative coins that command especially high prices before circulation.