Fine Gold Content
Also: Gold content, Gold fineness, Gold assay
Fine gold content states what proportion of a gold alloy consists of pure gold, expressed in thousandths (per mille) or in carats.
Fine gold content describes the percentage share of pure gold in a gold alloy. It is the decisive figure when buying, selling or valuing gold coins, gold bars and gold jewellery — because not every item called "gold" holds the same amount of the precious metal. The higher the fine gold content, the more valuable the piece is relative to its weight. The current gold price always refers to pure fine gold (999.9).
Units of measurement: per mille and carat
Fine gold content is expressed in two ways:
- Per mille (‰): the international standard notation, also called the "thousandths mark". 999 means 99.9% gold, 585 means 58.5% gold. On bars and coins this number is often struck into the piece (the fineness hallmark).
- Carat (kt): the traditional unit, used above all in the jewellery trade. The scale runs from 1 to 24 carat, with 24 carat corresponding to pure gold (999.9 ‰).
Conversion between the two units is straightforward:
Per mille = carat × (1000 ÷ 24)
Carat = per mille × (24 ÷ 1000)
Example: 18 carat × (1000 ÷ 24) = 750 ‰
Common fine gold contents at a glance
| Carat | Mark | Fine gold content | Typical use |
|---|---|---|---|
| 24 kt | 999 / 999.9 | 99.9% / 99.99% | Investment bars, bullion coins |
| 22 kt | 916 | 91.6% | Krugerrand, Sovereign (crown gold) |
| 21.6 kt | 900 | 90.0% | Vreneli, Napoleon (Latin Monetary Union) |
| 18 kt | 750 | 75.0% | Fine jewellery |
| 14 kt | 585 | 58.5% | Everyday and fashion jewellery |
| 9 kt | 375 | 37.5% | Jewellery in Ireland and the UK |
| 8 kt | 333 | 33.3% | Lower-grade gold jewellery |
Fine gold content and material value
For valuation, fine gold content is directly relevant: the melt value (also called material value) is the gross weight of a piece multiplied by the fine gold content and the current gold price. The melt value calculator works this out in seconds.
The fine weight — the weight of the pure gold contained — is calculated as follows:
Fine weight = gross weight × (fine gold content ÷ 1000)
Example: 10 g × (585 ÷ 1000) = 5.85 g fine gold
Buyers and refineries always pay on the basis of fine weight. A piece of jewellery in 750 gold weighing 20 g in total therefore holds 15 g of pure gold — and the buying price is calculated on that fine weight. The buying price calculator shows the expected proceeds according to fineness and weight.
Investment gold: special purity requirements
For VAT-exempt investment gold under the EU VAT rules (in Ireland, the VAT Consolidation Act 2010), minimum requirements apply:
- Bars: at least 995 ‰ fine gold content
- Coins: at least 900 ‰ fine gold content, legal tender in the country of origin
Classic investment bars from makers such as Heraeus, PAMP Suisse or Valcambi bear the mark 999.9 (the so-called "four nines"), the highest commonly available purity. Technically 999.99 (five nines) is possible, but it is barely seen in the investment segment.
Checking fine gold content
Several methods are available to determine fine gold content:
- Hallmark check: read the marks and fineness stamps on the piece (e.g. "750", "18K", "750/1000").
- Streak test: rubbing on a touchstone with acid — a quick dealer method, but imprecise.
- Acid test: reaction with nitric acid or aqua regia gives an indication of the content.
- X-ray fluorescence analysis (XRF): non-destructive, highly accurate measurement of the element content — the standard among professional buyers.
- Density test (Archimedes): comparing weight in air and in water allows conclusions about the alloy composition.
In brief
Fine gold content is the central figure for any gold item: it links weight and gold price to the real material value. Anyone who knows the fineness can use the gold calculator at any time to work out the exact worth of their gold — whether jewellery, coin or bar.