Gold is alloyed with other metals to make it stronger and more affordable. White gold is gold alloyed with a white or silver metal such as fine silver, nickel or palladium. All gold jewellery should bear a stamp or mark specifying the carat. The carat system indicates the gold content in parts of 24. For example 10-karat gold contains 10 parts gold and 14 parts of another metal.
24 carat is pure gold. It is not often used in jewellery because it is too soft and would break or bend during wear. It is marked with "24K."
18 carat is occasionally used in earrings or other pieces of jewellery that are less likely to be banged or bumped during wear. It is marked with "18K."
14 carat is the most commonly used carat for jewellery, including rings, necklaces and bracelets. It is marked with "14K."
10 carat is the lowest carat that may be sold as gold jewellery. It is sometimes used in rings because it is much stronger than the higher alloys. It is marked with "10K."
Gold-filled or gold-plated jewellery has very thin outer layers of gold with an inner layer of a base metal such as nickel. These pieces will be marked as "GF" or "GP," sometimes with a carat accompanying it such as "14K GF." Do not mistake this for gold jewellery, as it does not contain the minimum requirements of gold to be sold as such.