Gold Leaf
Also: Leaf gold, Sheet gold
Gold hammered or rolled into wafer-thin sheets, used in gilding, fine craft and food decoration.
Gold leaf is made either by mechanical rolling or by the ancient craft of gold-beating: a gold bar is first rolled into a fine ribbon, then laid between layers of parchment or plastic and driven out over several thousand hammer blows into wafer-thin sheets. The result is a foil typically 0.07 to 0.15 micrometres thick - thinner than a human skin cell. What makes this possible is gold's extraordinary ductility: of all metals it can be hammered and drawn the furthest without tearing.
Fineness and grades
Commercial gold leaf comes in various carat grades:
| Description | Carat | Fineness | Colour note |
|---|---|---|---|
| Genuine gold (transfer) | 23-24 kt | 958-999 | Rich yellow |
| Ducat gold | 23.5 kt | ~979 | Warm yellow |
| 22 carat | 22 kt | 916 | Slightly greenish |
| White-gold leaf | 12-18 kt | 500-750 | Silvery white |
For food (confectionery, pralines, drinks) only gold leaf carrying additive status E 175 is permitted - at least 22 carat (916), free of nickel and lead. The current gold price feeds straight into material cost, since even a few grams yield a considerable surface area.
Making it: gold-beating
The traditional craft breaks into three stages:
- Pre-rolling - the bar is rolled by machine to a ribbon about 0.1 mm thick.
- Cutching - pieces of ribbon are placed between skins and beaten by hand or machine to an intermediate thickness.
- Finishing - in a second packet the leaves are brought to final thickness and cut to the 80 x 80 mm format.
Area yield (approximation):
1 g Au x (1 / density 19.32 g/cm3) x (1 / thickness 0.00001 cm) = ~0.5 sq m
(thickness 0.00001 cm = 0.1 um, typical hand-beaten leaf)
Where it is used
- Gilding of picture frames, sculptures, church furnishings and architectural details
- Sign and book gilding (bookbinding, signage, glass gilding)
- Cuisine - E 175 on pralines, in digestifs and on desserts
- Medicine / cosmetics - face masks and, occasionally, wound coverings (mild antimicrobial effect of low gold concentrations)
- Electronics - ultra-thin contact coatings in specialist applications
A direct material value can be found at any time with the gold calculator or the melt value calculator - relevant, for example, when buying gilded objects whose gold content is minimal.
Genuine gold versus imitation
"Composition leaf" or "imitation gold leaf" made of brass or copper-zinc alloys looks similar but tarnishes and is far cheaper. It is distinguished by the fineness mark; on loose leaves, an acid test or a gold-testing device tells the two apart.
In a nutshell
Gold leaf blends a craft tradition thousands of years old with modern industrial use. Fineness and thickness decide both quality and price - together they determine whether a leaf suits elegant gilding, food, or technical purposes.