The fineness of gold is the purity measures in karats or as a percentage number.
There are several different types of gold along with the various quality levels and the quality is often referred to as the ‘Fineness of Gold.’ Fineness, or the number of Karats commonly falls between 9 karats and 24 carats with 24 being the purest gold sometimes called 99.999 Fine gold. Different types include the well-known yellow gold, this is mixed with silver, copper and zinc in various ratios. Blending in this way gives a gold alloy that is harder-wearing than the pure gold element making it more suitable for wearable rings and jewellery. Higher amounts of the less expensive base metals such as copper mean the gold has a lower value weight-for-weight in relation to its purest form. This is why there are different numbers of karats, 9 karat having a lower gold content than 22 karat. White gold includes palladium with zinc and nickel. Rose gold has silver and high levels of copper making it more affordable and much harder wearing.
To find out what fineness your gold items are its sometimes possible to look for the Hallmarks if it is hallmarked. These can tell us some information about where and when the item was made along with the quality. Gold rings are generally marked inside the band where you might see the actual stamp for ‘9 karat’ making things easy. If you see a number then this can be converted into karats, it is a percentage of fine gold so 375 will be 9 karat, 750 is 18 karat and 916 is 22 karat. A strong magnifying glass does help, a gold dealer will use a loupe. For bracelets and necklaces the hallmark will be on the underside clasp of the chain. Coins such as the well known sovereigns, American Gold Eagles and krugerrands don’t have hallmarks but they should match the correct weight and will be minted from 22 karat gold and the popular Britannia can be 22 or (from 2013) 24 karat with the 22 weighing slightly more due to the alloying metal added to the ounce of gold.