750 Gold: The International Standard for Fine Jewellery
750 Gold: The International Standard for Fine Jewellery
18-karat gold and its role in European, Middle Eastern, and Asian jewellery traditions
750 gold — expressed in millesimal fineness as 750/1000, and equivalent to 18-karat (18ct) gold — is an alloy containing exactly 750 parts pure gold per 1,000 parts by weight, or 75 per cent fine gold. It is the dominant standard for fine jewellery across Europe, the Middle East, and much of Asia, and is the alloy of choice for the overwhelming majority of gem-set pieces produced by the great French, Italian, and Swiss maisons. Its combination of rich colour, workability, and prestige has made it the benchmark against which other gold standards are measured in the international trade.
Composition and Alloying Metals
The remaining 250 parts per thousand — 25 per cent of the alloy by weight — consist of one or more base or precious metals chosen to modify colour, hardness, and working properties. The principal alloying elements are copper, silver, palladium, and nickel, used in varying proportions to produce the three commercially dominant hues:
- Yellow 750 gold is typically alloyed with silver and copper in roughly equal measure, preserving the warm, saturated yellow associated with high-purity gold while improving tensile strength and castability.
- Rose (or pink) 750 gold achieves its characteristic warm blush through a higher proportion of copper relative to silver. The precise copper-to-silver ratio determines whether the result reads as a pale champagne pink or a deeper rose-red.
- White 750 gold is produced by alloying with palladium, nickel, or a combination of silver and palladium. Palladium-based white gold is the preferred formulation in contemporary fine jewellery, as nickel is a recognised skin sensitiser and is restricted or prohibited as a jewellery alloying metal under European Union Directive 94/27/EC and its successor regulations. White 750 gold is frequently rhodium-plated at the surface to achieve a brighter, more reflective finish and to further reduce any residual warmth in colour.
The choice of alloying metals also affects the alloy's response to heat treatment, its suitability for different fabrication techniques (casting, forging, die-striking, hand-fabrication), and its long-term tarnish resistance. Palladium-bearing alloys, for example, are notably resistant to surface oxidation.
Hallmarking and Legal Standards
Across the jurisdictions where 750 gold is most prevalent, independent hallmarking by an assay office or equivalent authority is either legally required or strongly conventional. The millesimal mark 750 is the internationally recognised numerical stamp, and it appears on virtually all pieces sold in Italy, Switzerland, Germany, and across the Gulf Cooperation Council states.
In France, the traditional guarantee mark for 18-karat gold is the poinçon de garantie depicting an eagle's head (tête d'aigle), introduced in its modern form in 1838 and administered by the French customs and excise authority. The eagle's head mark is one of the most recognisable hallmarks in the world of fine jewellery and functions as a legal guarantee that the article meets the 750/1000 standard. Imported pieces entering France that do not already carry a recognised foreign hallmark must be submitted for assay and, if conforming, receive the eagle's head before retail sale.
In the United Kingdom, 18-carat gold is hallmarked by one of the four active assay offices (London, Birmingham, Edinburgh, and Sheffield) with the millesimal figure 750 alongside the assay office's own sponsor's mark and date letter. The UK also participates in the Vienna Convention on the Control of Articles of Precious Metals (the Hallmarking Convention), which provides for mutual recognition of conforming hallmarks among signatory states.
In Italy, the 750 stamp is the standard mark, and Italian pieces frequently carry it alongside a maker's code registered with the Italian Chamber of Commerce. Italy's position as one of the world's largest manufacturers and exporters of gold jewellery — centred historically on Vicenza, Valenza, and Arezzo — has made the Italian 750 stamp familiar to buyers and traders worldwide.
In the United States, the karat system prevails, and 18-karat is the conventional description. Federal Trade Commission guidelines require that any karat designation be accurate to within a tolerance of half a karat, and the abbreviation 18K or 18KT is the standard trade notation.
Physical and Working Properties
Pure gold (24-karat, 999/1000) is too soft for most jewellery applications: it scratches readily, deforms under normal wear, and cannot hold a prong or bezel securely around a stone. Alloying to 750/1000 raises the Vickers hardness from approximately 25 HV for annealed fine gold to a range of roughly 120–230 HV depending on alloy composition and heat treatment — sufficient for the fine detail work, engraving, milgrain edging, and secure stone-setting that characterise fine jewellery manufacture.
Compared with 14-karat gold (585/1000), 750 gold is somewhat softer and therefore more susceptible to surface scratching over years of daily wear. This is a known trade-off accepted by the market: the higher gold content produces a richer, more saturated colour that does not fade or alter with wear, and the alloy's lower base-metal content reduces the risk of allergic contact dermatitis in sensitive wearers — particularly relevant where nickel-free palladium alloys are used.
The density of 750 yellow gold is approximately 15.5 g/cm³, compared with roughly 19.3 g/cm³ for fine gold and approximately 13.0 g/cm³ for 14-karat yellow gold. This difference in density is perceptible in finished pieces and contributes to the characteristic weight and presence that buyers associate with high-quality jewellery.
Market Position and Trade Context
In the European fine jewellery trade, 750 gold is effectively synonymous with quality. Auction houses including Christie's, Sotheby's, and Bonhams routinely describe gem-set lots as being in 18-karat or 750 gold as a primary quality indicator, and the mark's presence on a piece is taken as evidence of manufacture to a recognised standard. Signed pieces by major maisons — Cartier, Van Cleef & Arpels, Bulgari, Chopard — are almost invariably in 750 gold, and the alloy's association with these names reinforces its prestige positioning.
In the Gulf states and across much of the Middle East, 750 gold competes with 21-karat and 22-karat alloys that are preferred in certain traditional jewellery markets for their deeper colour and higher intrinsic gold content. However, for gem-set fine jewellery and branded pieces, 750 remains the standard of choice, as the higher-karat alloys are generally too soft to hold stones securely in prong or pavé settings.
In East and Southeast Asia — particularly in Hong Kong, Singapore, and Japan — 750 gold is the standard for gem-set jewellery sold through department stores and fine jewellery retailers, while 999 (24-karat) gold retains cultural importance for investment pieces and ceremonial gifts.
The gold content of a 750 alloy piece has direct implications for valuation: at any given gold spot price, the intrinsic metal value of a 750 piece is 75 per cent of that of an equivalent weight of fine gold. However, in the secondary market for signed or antique jewellery, craftsmanship, provenance, and gemstone quality invariably dominate over melt value.