585 gold is a gold alloy containing exactly 585 parts pure gold per 1,000 parts total weight — equivalent to 14-karat (14ct or 14K) gold, representing 58.5 per cent fine gold by mass. It is the single most widely used gold standard in fine jewellery manufacturing across Germany, the United States, and much of continental Europe, prized for its practical equilibrium between precious-metal content, mechanical hardness, and commercial accessibility. The designation "585" is the millesimal fineness expression of the same composition that English-speaking markets label 14ct or 14K.

Composition and Alloying Metals

The remaining 41.5 per cent of a 585 gold alloy — 415 parts per 1,000 — consists of base and semi-precious metals whose precise proportions are adjusted by the manufacturer to achieve a specific colour, hardness, or working characteristic. The principal alloying elements and their effects are as follows:

• Copper deepens the alloy toward warm, reddish tones; high copper concentrations yield the rose and red gold variants popular in contemporary jewellery.
• Silver lightens and slightly greenifies the hue; silver-dominant additions produce the greenish-yellow tones sometimes marketed as "green gold."
• Zinc is commonly added in small quantities to improve fluidity during casting and to lighten colour.
• Nickel was historically the primary whitening agent in European white-gold alloys; it produces a hard, bright white but is now restricted in the European Union under the Nickel Directive (EU Directive 94/27/EC and its successor 2004/96/EC) owing to its potential to cause contact dermatitis.
• Palladium has largely replaced nickel as the whitening agent of choice in EU-compliant white 585 gold, producing a softer, slightly warmer white with excellent biocompatibility.

Standard yellow 585 gold is typically alloyed with a combination of copper and silver in roughly equal proportions, yielding the characteristic warm, slightly muted yellow that distinguishes 14ct pieces from the richer, more saturated tone of 18ct (750) gold. The lower gold content produces a perceptibly cooler, less saturated yellow, a difference that trained eyes can detect in direct comparison.

Mechanical Properties

Pure gold (999 or 24ct) is exceptionally soft — approximately 25 on the Vickers hardness scale in its annealed state — and unsuitable for most jewellery applications without alloying. The addition of 41.5 per cent base metals raises the Vickers hardness of a typical yellow 585 alloy to approximately 120–150 HV (work-hardened), compared with roughly 175–230 HV for a comparable white 585 nickel alloy. This hardness range makes 585 gold significantly more resistant to scratching and deformation than 750 (18ct) gold, and considerably more so than 999 or 958 (23ct) gold. The practical consequence is that prong settings, thin shanks, and fine milgrain details hold their form better over decades of wear in 585 gold than in higher-purity alloys — a consideration of genuine importance for engagement rings and everyday jewellery.

The alloy also exhibits good ductility for wire drawing and good malleability for rolling into sheet, though its higher base-metal content makes it marginally more prone to porosity in casting if foundry conditions are not carefully controlled.

Hallmarking and Legal Standards

Hallmarking requirements for 585 gold vary by jurisdiction, though the millesimal fineness mark "585" is recognised internationally as the standard designation under the Vienna Convention on the Control of Articles of Precious Metals (the Hallmarking Convention), to which numerous European states are signatories.

• Germany: German law has historically required that gold articles offered for sale as 585 gold bear the "585" fineness mark, either struck by an official assay office or, under more recent regulations, applied by the manufacturer under a system of self-declaration with legal liability. The German market is one of the largest consumers of 585 gold jewellery in the world, and the standard is so entrenched that "585" functions almost as a synonym for fine gold jewellery in everyday German usage.
• United States: American pieces are stamped "14K" or "14KT" in accordance with Federal Trade Commission guidelines, which require that any article described as 14-karat gold contain no less than 14 parts gold per 24 (i.e., not less than 58.33 per cent). A tolerance of 0.003 parts per 24 below the stated fineness is permitted. The "585" mark also appears on US-made pieces destined for export to European markets.
• United Kingdom: The UK Hallmarking Act 1973 (as amended) recognises 585 as a standard of fineness for gold, and articles assayed at the UK's four assay offices (London, Birmingham, Edinburgh, Sheffield) may bear the millesimal fineness mark 585 alongside the assay office sponsor's mark and date letter.
• Italy: Italy, one of the world's foremost jewellery manufacturing centres, uses the millesimal system; 585 gold is widely produced in Vicenza and Arezzo for both domestic consumption and export.

Colour Variants

The three principal colour expressions of 585 gold — yellow, white, and rose — are all produced at the same gold fineness, with colour determined entirely by the alloying formula.

Yellow 585 gold is the traditional form, typically alloyed with copper and silver. Its colour is noticeably less saturated than 750 yellow gold, a characteristic that some buyers prefer for its subtlety and others find less desirable.

White 585 gold in its palladium-alloyed form is a light greyish-white that is frequently rhodium-plated at the point of manufacture to achieve a bright, mirror-white surface. The rhodium plating is a surface treatment, not a change in alloy composition, and will wear away over time with normal use, requiring periodic re-plating. Nickel-alloyed white 585 gold, still encountered in older pieces and in some non-EU markets, is harder and whiter but carries the sensitisation risk noted above.

Rose 585 gold — sometimes called pink gold or, at higher copper concentrations, red gold — is produced by increasing the copper proportion, typically to 20–25 per cent of the total alloy weight. Rose gold has experienced sustained commercial popularity since approximately the early 2000s, and 585 rose gold is among the most commercially significant variants in contemporary bridal and fashion jewellery.

Market Position and Trade Significance

In the context of the global fine-jewellery market, 585 gold occupies a distinct commercial niche between the prestige positioning of 750 (18ct) gold — the standard of choice for high jewellery, signed pieces, and most Swiss watch cases — and the lower price point of 375 (9ct) gold, which is the dominant standard in the United Kingdom and Ireland for volume jewellery. The United States market has historically shown a strong preference for 14K over both 18ct and 9ct, reflecting a consumer expectation that fine jewellery should be durable enough for daily wear without commanding the premium of higher-purity alloys.

The price differential between 585 and 750 gold is directly proportional to their gold content: a given weight of 585 gold contains approximately 22 per cent less fine gold than the same weight of 750 gold, a saving that is passed through to the consumer and makes 585 the accessible entry point for diamond solitaire rings, gemstone jewellery, and chain in most Western markets.

For the gemmologist and jewellery specialist, identifying 585 gold in unmarked or worn pieces requires either acid testing (the 14K acid test solution will not dissolve a 585 alloy) or, more reliably, X-ray fluorescence (XRF) analysis, which provides a non-destructive compositional reading accurate to within fractions of a percentage point. Reputable gemmological laboratories including those operating under GIA, as well as independent assay offices, routinely perform such analyses for trade and insurance purposes.

Further Reading

• GIA — Gold Alloys in Jewellery
• AGTA — Precious Metal Care and Standards