Fineness
Also: Purity, Degree of purity, Fine gold content, Carat
Fineness indicates how much pure precious metal is contained in an alloy – expressed in thousandths (e.g. 999) or in carats (e.g. 585 = 14 carat).
Fineness – also called purity – describes the proportion of pure precious metal in an alloy. Pure precious metals are too soft for many purposes, which is why they are mixed with other metals (such as copper, silver or palladium). The fineness states how high the proportion of the actual precious metal is in this mixture.
Two notations: thousandths and carats
There are two common notations:
- Per mille / thousandths: 999 means 999 out of 1000 parts are fine gold – that is 99.9 %. This figure appears today on almost all bars and bullion coins.
- Carat (for gold): here 24 carat = 100 % fine gold. 18 carat corresponds to 18/24 = 750/1000.
The most important gold alloys at a glance:
| Carat | Fineness | Fine gold content |
|---|---|---|
| 24 kt | 999 | 99.9 % |
| 22 kt | 916 | 91.6 % |
| 18 kt | 750 | 75.0 % |
| 14 kt | 585 | 58.5 % |
| 8 kt | 333 | 33.3 % |
Why fineness determines the value
The material value of a piece of jewellery depends directly on the fineness. A 585 gold ring contains only 58.5 % fine gold – the rest is copper and silver, which contribute little to the precious metal value. To calculate the pure metal value (the melt value), you multiply the weight by the fineness and the current gold price. This is exactly what the melt value calculator does automatically – even for mixed lots of 333, 585 and 750 gold.
Fineness hallmark
In Malta and other EU countries, precious metal articles may bear a hallmark that indicates the fineness – for example "750" for 18-carat gold or "925" for sterling silver. Malta is a signatory to the Vienna Hallmarking Convention, and the stated fineness must correspond to the truth. With dental gold the hallmark is often missing entirely; here the specialised dental gold calculator helps, which assumes typical alloys between 750 and 900.
In brief
Fineness is the key to material value: without it, no reliable value can be derived from weight and daily price. Anyone wishing to value jewellery or broken gold should always first determine the fineness – via the hallmark or an expert test.