Définition

• White Metal.  An alloy with a base of tin, with or without lead, and any of several other medals – copper, antimony, bismuth for the most part. The resulting color can be silver- white to gray depending upon the dominance of the tin or lead (and whether the piece has toned). If tin is the more dominant element it is whiter in color; if lead, it is more gray. White metal is not a specific composition and its formulation cannot be distinguished by inspection alone. Tin is always present, with one or more of the above mentioned metals, tiny quantities of other metals may also be present, even zinc, nickel or silver.
  White metal is closely related to pewter. Also white metal has several synonyms and has been called a number of terms in various commercial applications. These include; alpacca, argentine, Babbitt metal, britannia metal (or simply britannia), British plate, hard metal, prince's metal, white brass, even Queen's metal. The use of white metal was widespread in Great Britain where an entire industry existed in the 18th and 19th centuries to manufacture such objects.
  Tin and pewter had been worked by man for centuries, tin having been known since prehistoric times. Pewter was known in Greek and Roman times and in use in Great Britain before 1000. The tin mines of Wales and Cornwall supplied England with an ample supply of quality metal. By the 1700s British pewter workers were quite skilled with guilds to protect the quality of their finished products. By the mid-18th century, however, a few such workers sought to improve their product more so.
  Working in secret metal workers developed an alloy that was an improvement
  over the tin and lead composition of pewter. We know today their secret was to add copper and antimony. An account published in 1834 gave credit to two Sheffield workers known only as "Jessop and Hancock" but this account also stated the new metal was formed by adding melted copper, antimony and brass to molten tin. The alloy was harder than pewter, brighter, easier to work and – best of all – it did not require the constant polishing that pewter does. A contemporary account in 1769 called it "Vicker's" white metal.
  First white metal medals.  Objects of white metal must have been made in 1760 or before because the first medals of the new composition were struck for the marriage of George III and Queen Charlotte in 1761 and also two medals for the coronation later that same year (Brown 17, 34, 64).
  In the next forty years, to the end of the 18th century, over 100 medals appeared in white metal. The bulk of the medals then – as for white metal medals of all times – were not the elegant, important, costly issues, but instead were the souvenir, low-cost medals, the kind that were sold to the public, often hawked to the people on the streets. Mostly they were holed or looped so they could be worn (because of their light weight), they were struck for public occasions like a coronation or struck for a society that could not afford a more expensive metal, like a temperance society.
  White metal was later called britannia for most of the utensils and tableware made of the composition, for teapots, tankards, candlesticks and lamps. It was desired over pewter for its bright color and ease of maintenance. Attempts to make rolled plate with britannia and silver (a kind of Sheffield plate) were unsuccessful in the 1820s. However the development of silverplating in the late 1840s in Great Britain found white metal could be satisfactorily silverplated; but its light weight was less desirable than the heavier copper alloys of brass and bronze. White metal had been gilded and bronzed on medals as early as 1805 and 1809.
  Three series of medals were issued in Britain 1828-30, all of which were issued in white metal (and all published by Edward Thomason):  Medallic Illustrations of Science and Philosophy, the Kings and Queens of England, and Thomason's famed Medallic Bible.
  It is estimated that over half of all the medals issued in Great Britain in the 19th century were made of white metal (over 40% of all listed in Brown were struck in white metal and there are others not listed in Brown). Two-thirds were medal issues with other compositions as well – with white metal for the cheapest alloy, usually in the greatest quantity.
  Numismatic aspects.  When white metal is freshly struck it is light silver color with a small degree of reflectiveness. Numismatists call this untarnished shinny state bright. When white metal tones – loses reflectiveness and turns gray – this is called darkening (a form of clouding). Darkening is due in large part to the tin content. As tin is subjected to temperature fluctuations and drops below 18° C it turns gray; as tin ages with repeated cold environments it can form a corrosion called tin pest (untreated tin pest could result in grayish powdery deposit gradually covering the object's surface).
  Normal medallic finishing – of oxidizing and relieving – is not practical for white metal. White metal cannot take a patina finish (because of the properties of tin) and, for the most part, struck white metal pieces are left in their coined finish. (Lacquer would help, but this was very seldom done for low-cost pieces.)
  White metal is fairly soft – too soft for coins – though somewhat harder than either tin or lead in pure state; it is quite malleable but is not very ductile. As
  such it does not work harden. Certain white metals – those containing antimony – cannot be turned on a lathe. Other formulas of white metal can, and in fact, are fashioned into spun objects on a lathe. The metal is ideal, as mentioned, as a base for plating including gold and silver. Its low weight makes excellent pendant medals to be worn.
  White metal is also excellent for striking. Because of its own soft state it is often
  the first of several compositions to be struck, certainly before those of harder alloys, (to lessen the chance of breaking a die). In rare instances when medals were cast of white metal they exhibit less of the casting problems of bronze – fewer surface nodules form, for example, and less of a need for chasing.
  White metal was created as an imitation of pewter, which was in imitation of silver or silverplate. Ironically, even white metal was imitated – with an alloy of zinc; spelter. Spelter is more than half zinc combined with nickel and tin.
  Medals of white metal were struck into the 20th century. With the rise of popularity of aluminum, particularly after 1890 with the low cost electrolytic method of extracting pure aluminum from aluminum oxide ores, led to the decline of white metal and the rise of aluminum for inexpensively struck medals and low-value coins.
  White metal surface displacement.  White metal has the strange property, frequently appearing on medals, that an area of great surface stress will not tone. Lettering – particularly close to the border – is formed from surface mass drawn inward toward the center of the struck piece. The areas where this metal is drawn from – in effect metal flow – becomes work hardened and will continue to be bright while the remainder of the surface will tone.
  This property gives a reverse "shadow" effect to some lettering. The shadow, however, is bright and remains so for decades, even centuries. The piece may turn from gray to black, but the surface displaced area remains bright!
  White metal is abbreviated WM (and in French is called metal blanc). Early catalogers or inexperienced numismatists sometime confuse it with tin; also some medals described as tin or pewter, may indeed be white metal; but this is all because it is difficult to identify the exact composition by inspection alone. (X-ray fluorescence and spectrography are necessary to scientifically identify the precise metallic content and thusly the precise composition of any light gray coin or medal, but this is seldom done.  The term "white metal" usually is sufficient description for a light weight metal in light gray color.
  See composition (2).
  References:                                                                                                                                  
  NC5 {1964} Peck, p 225, note 1.

  excerpted with permission from

  An Encyclopedia of Coin and Medal Technology

  For Artists, Makers, Collectors and Curators

  COMPILED AND WRITTEN BY D. WAYNE JOHNSON

  Roger W. Burdette, Editor

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