Are British gold sovereigns really made of gold?

The modern British gold sovereign is a 22-carat gold coin, a specification that has remained standard from 1817 until the present, as of 2015. A coin with 22 carats has 91.67 percent of its total mass made of pure gold.

The first gold sovereigns were minted during the reign of King Henry in 1489. These were larger than modern sovereigns and were primarily used as a political statement to demonstrate the wealth of the monarchy. In 1817, sovereigns were reinstated as a 7.98-gram coin made of 22-carat gold, about half the weight of the old sovereigns. These specifications are the same as those of modern Sovereigns, which are printed most years and primarily intended as collector's items..