Rolled Gold / Gold Doublé
Also: Doublé, Gold-filled, Rolled gold, Double
Rolled gold is a base-metal core (usually brass or copper) that is mechanically bonded to a thick layer of gold by hot rolling – in contrast to electrolytic gold plating.
Rolled gold (also gold doublé, gold-filled or rolled gold) refers to a composite material in which a relatively thick layer of gold is permanently bonded to a base carrier material – usually brass, copper or nickel silver – by mechanical hot rolling or pressing. The result is visually almost indistinguishable from solid gold, but contains only a fraction of the gold value.
Manufacture and structure
In the rolled-gold process, a sheet of gold (usually a 333 to 750 alloy) is rolled together with the base metal at high temperature until the two layers form an inseparable metallic bond. The gold layer makes up at least 1/20 of the total weight (the American gold-filled standard) and, at 20–100 micrometres, is considerably thicker than electrolytic gold plating (0.1–5 µm). This layer thickness gives rolled gold considerably better wear resistance.
Distinction: rolled gold, plating, doublé
| Feature | Rolled gold | Electrolytic plating | Solid gold |
|---|---|---|---|
| Bond | Mechanical (rolling) | Electrolytic | Monolithic |
| Layer thickness | 20–100 µm | 0.1–5 µm | Solid material |
| Gold share of weight | approx. 5 % | < 0.1 % | 100 % |
| Durability | High (years to decades) | Low to medium | Permanent |
| Total fineness | below 333 ‰ | below 333 ‰ | depending on alloy |
Important: Since the fineness of the whole item is usually below 333 per mille, rolled gold is not classed as a precious metal in the legal sense and must not be stamped with a hallmark for genuine gold.
Marking and legal position
In the UK and the EU, rolled gold must be clearly marked as such – typical inscriptions are GF (gold-filled), RG (rolled gold), Doublé or a specification such as 20/1000 GF 14K. A misleading description as "gold" or a genuine gold hallmark is prohibited. In the USA, the FTC Jewelry Guides set the minimum requirements for gold-filled jewellery.
You can estimate the actual material value with the melt value calculator – although with rolled-gold pieces only the weight of the gold layer is relevant, not the total weight. Whether a piece is really rolled gold or genuinely solid gold is revealed by a coin authenticity check or a professional streak/acid test at a jeweller.
Formulae for the gold content
Gold weight = total weight × (layer share / 1000) × (fineness carat / 24)
Example: 10 g bracelet, 1/20 GF, 14K → 10 × 0.05 × 0.583 ≈ 0.29 g fine gold
In brief
Rolled gold offers the visual lustre of gold at a fraction of the price, but has no meaningful material value as a precious metal. For purchase and melting, the actual fine gold content is decisive – this can be determined with the purchase price calculator once the layer parameters are known.