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Precious Metals: Hallmark System

Precious Metals Hallmarking

The modern Hallmarking System started in London, England in the 1300s to protect the public against fraud from unscrupulous sellers. Due to the high value of pure gold, silver and platinum, there is a great deal of temptation to increase profits by reducing the precious metal content of an alloy during the manufacturing of coins, jewelry, flatware, and other valuable metal art objects.

Hallmarking is an official designation that can only be added to an item after it has been assayed to determine its purity by an Assay Office. A hallmarking designation is significantly different than a voluntarily marking of "fineness" that is made by a manufacturer, as there is no way to verify the manufacturer's accuracy.

Metals Hallmark Symbols & System

Traditionally, hallmarks are stamped, or "struck" into the metal using a steel punch, but laser-marking is now replacing the punch method by many Assay offices.

Hallmark symbols consist of four "compulsory Marks." The "date" hallmark became optional in 1998, but the other three symbols are still compulsory. The symbols give the following information:

  • Sponsor or Maker: Who made the piece.
  • Standard Mark: The guaranteed standard of fineness or purity.
  • Assay Office: The Assay Office that tested and marked the item.
  • Date: The year the item was tested and marked.
The "standard" hallmark indicates the "fineness" or purity of the metal alloy. In the case of Sterling Silver, the "925" Hallmark indicates that there are 925 parts of pure sliver per 1,000 total parts.

International Hallmark Convention

In 1972 the International Convention of Hallmarks (Hallmarking or Vienna Convention) was established to standardize the identification system across geographic boundaries. Countries that signed on to the Convention are: Austria, The Czech Republic, Denmark, Finland, The Netherlands, Norway, Portugal, Sweden, and Switzerland. In 1975, the Hallmarking Act was enacted to include the Platinum marking standardization.

Silver Hallmarking Stamp

Hallmarking stamp

   Silver Sterling Stamp

Silver 'sterling' stamp without hallmark

Changes to the United Kingdom (UK) hallmarking system were made in 1999, in order to bring the system in line with the current European Union (EU) standards.

Metals Hallmarking Symbols

The Hallmarking of precious metals is still a legal requirement in the United Kingdom. The Birmingham Assay Office is the largest Assay Office in the World, testing and marking over 12 million items per year.

Bibliography on Hallmarks and the Hallmarking System

1. The Birmingham Assay Office . www.theassayoffice.co.uk

2. Convention on the Control & Marking of Precious Metals . www.hallmarkingconvention.org

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