Estimate an indicative fine-gold percentage from measured density using an explicit two-component mixture model. Choose the assumed non-gold reference material to see how the result changes, and compare the measured density with common gold-karat reference ranges.
Screening model — not an assay.
Gold purity is not uniquely encoded in density. An alloy can contain different combinations of silver, copper, zinc, palladium and other metals while having different densities at the same nominal karat.
This calculator therefore does not present its output as an assay. Instead, it shows the result of a clearly stated two-component model.
Here, x is the modelled mass fraction of fine gold, ρgold is the reference density of pure gold, ρalloy is the assumed density of the non-gold component and ρmix is the measured sample density.
A density of 15.5 g/cm³ does not correspond to one unique gold percentage. A model assuming a silver-rich non-gold component can produce a different estimate from a model assuming copper or zinc.
| Reference | Approx. Density | Role |
|---|---|---|
| 24K / Pure Gold | 19.32 g/cm³ | Pure-gold reference |
| 22K Gold | ~17.5 g/cm³ | Approximate alloy reference |
| 18K Gold | ~15.5 g/cm³ | Approximate alloy reference |
| 14K Gold | ~13.1 g/cm³ | Approximate alloy reference |
A density result can help screen for obvious inconsistencies, compare an object against material references and decide whether further testing is worthwhile. It cannot reliably identify exact karat when the composition or construction is unknown.
Hollow construction, stones, solder, plating, cavities and trapped air can all distort the effective density of a finished jewellery item.
Use this page as a mathematical screening tool. For high-value jewellery, commercial settlement, manufacturing control or certification, use an appropriate assay or professional analytical technique.
Only as a model-based screening estimate under stated assumptions. Density alone cannot uniquely determine purity.
A common reference value is 19.32 g/cm³.
It can support a comparison, but not conclusively determine karat.
The model needs an assumed non-gold component to solve the mixture equation.
No. It is a screening calculation, not a laboratory assay.