Silver-gilt

Silver-gilt is silver (either pure or sterling) which has been gilded. Most large objects made in goldsmithing that appear to be gold are actually silver-gilt; for example, most sporting trophies (including medals such as the gold medals awarded in all Olympic Games after 1912) and many crown jewels are silver-gilt objects.

Apart from the raw materials being much less expensive to acquire than solid gold of any karat, large silver-gilt objects are also noticeably lighter, as well as more durable. (Gold is about 1.7× heavier than lead and 1.8× heavier than silver and is easily scratched and bent.) For objects that have intricate detail such as monstrances, gilding greatly reduces the need for cleaning and polishing, and so reduces the risk of damage. Ungilded silver would suffer oxidation and need frequent polishing; gold does not oxidize at all. The "gold" threads used in embroidered goldwork are normally also silver-gilt.

A similar material is gilt-bronze, also known as ormolu. Vermeil is an alternative for the usual term silver-gilt. It is a French word adopted into American English language in the 19th century, and is rare in British English. "Vermeil" can also refer to gilt bronze, a material even less costly than silver.

Techniques

The addition of a thin layer of gold to silver objects has been known since antiquity. 'Layering', folding or hammering on gold leaf or silver leaf is mentioned in Homer's Odyssey (Bk vi, 232), and gilding with mercury dates back to at least the 4th century BC. Pliny the Elder suggests that this technique was in use by the first century AD. This technique of adding a surface layer of gold should not be confused with the method used by the Incas, which consisted of stripping the copper from the surface of a gold-copper alloy, tumbaga, known as the "depletion gilding" method.

Fire-gilding with mercury dates to at least the 4th century BC, and was the most common method until the Early Modern period at least. However, it put workers at risk of mercury poisoning and often caused blindness among French artisans who refined the technique in the 18th century. Electroplating is now the most commonly used method: it involves no mercury and is therefore much safer. Keum-boo is a special Korean technique of depletion gilding. In China gilt-bronze, also known as ormolu, was more common.

Today, electroplating is the most commonly used method. Once widely used in jewelry and cutlery for its durability, it was abandoned due to its high cost.

Use

Most large goldwork that appears to be gold is actually silver-gilt; this is the case with many crown jewels (for example, the English Crown Jewels sold in the 17th century after the execution of King Charles I) and sports trophies (the "gold medals" at every Olympic Games since 1912).

Compared to ordinary silver, for delicate objects like the Nave, or those with intricate details like monstrances, gilding greatly reduces the need for cleaning and polishing, and thus reduces the risk of damaging them.

The Burghley silver-gilt nave, made in France in 1527-1528. In 2011, at the Victoria and Albert Museum in London.

Hygiene

Vermeil does not cause allergies because it is silver coated with gold, two hypoallergenic metals. The bond between the two metals (molecular adhesion) results in a "gold plating" treatment of exceptional resistance.

Considerations in use

Silver objects can be gilded at any point, not just when first made, and items regularly handled, such as toilet service sets for dressing-tables or tableware, often needed regilding after a few years as the gold wears off. In 18th century London, silversmiths charged 3 shillings per ounce of silver for an initial gilding, and 1 shilling and 9 pence per ounce for regilding. In parcel-gilt cups, only the interior is gilded, perhaps to prevent contamination of drinks with tarnish cleaning chemicals.

Fully silver-gilt items are visually indistinguishable from gold, and were no doubt often thought to be solid gold. When the English Commonwealth sold the Crown Jewels of England after the execution of Charles I they were disappointed in the medieval "Queen Edith's Crowne, formerly thought to be of massy gold, but upon trial found to be of silver gilt", which was valued at only £16, compared to £1,110 for the "imperial crowne". The English Gothic Revival architect Sir George Gilbert Scott was concerned by the deception in this. He accepted gilding of the interior only, but with all-over gilding "we... reach the actual boundary of truth and falsehood; and I am convinced that if we adopt this custom we overstep it.... why make our gift look more costly than it is? We increase its beauty, but it is at the sacrifice of truth." Indeed, some Early Medieval silver-gilt Celtic brooches had compartments apparently for small lead weights to simulate the weight of solid gold.

Regulations by country

In Canada, the Competition Bureau (precious metals section) gives the following definition: quality marks (vermeil or vermil) used for vermeil can only be affixed to items containing at least 92.5% silver and plated with gold of at least 10 micrometers.

By US Code of Federal Regulations 16, Part 23.4: "An industry product may be described or marked as 'vermeil' if it consists of a base of sterling silver coated or plated on all significant surfaces with gold, or gold alloy of not less than 10-karat fineness, that is of reasonable durability and a minimum thickness throughout equivalent to two and one half (2+1⁄2) microns (or approximately 100⁄1000000ths of an inch) of fine gold."

For France, there must be a minimum thickness of 5 micrometers of 750/1000 gold, on 950 or 800/1000 French silver. It is the silver hallmarks present that allow us to speak of vermeil, when the silver is gold-plated under these conditions. Vermeil is also used for the manufacture of the Grand Cross plaque of the Legion of Honor. On objects weighing more than 30g in vermeil, a hallmark with the letter "V" in a diamond must accompany the mark of the silver hallmark.

In Great Britain, silver is 925/1000 Sterling.

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