Signature hallmarks

For the manufacturing of jewellery and silverware, precious metals are not used in their purest forms. Instead, they are alloyed with other metals. It is not possible to discern by sight or by touch what the precious metal content of an alloy is.

In the UK, the consumer enjoys a guarantee of the precious metal content through the 700-year-old practice of an independent third party: Hallmarking.

The 1973 Hallmarking Act makes it unlawful to describe an item over a certain weight as gold, silver or platinum without an independently applied Hallmark.

  • All Silver articles weighing more than 7.78 grams must be hallmarked.
  • All Gold articles weighing more than 1 gram must be hallmarked..
  • All Platinum articles weighing more than 0.5 grams must be hallmarked.

The “Who, What and Where” of Hallmarking:


This is known as the sponsor’s mark. This mark is the registered mark of the person or company who made or submitted the items for testing and marking. In the case of Tateossian jewelry, “RT” represents the name of the designer, Robert Tateossian.


This mark is known as the fineness or purity mark and describes the precious metal content, expressed in parts per thousand. There is a different shaped shield for each precious metal (see the examples below).


This is known as the Assay Office Mark and tells the purchaser where the item was tested. There are four UK Assay Offices; Edinburgh, London, Sheffield and Birmingham.

THE UNITED KINGDOM ASSAY OFFICES have joined forces to launch a commemorative hallmark to celebrate HM The Queen’s Diamond Jubilee in 2012. Known as the Diamond Jubilee Mark, this special commemorative mark, approved by the British Hallmarking Council, depicts a young Queen Elizabeth wearing an oversized crown in a diamond shaped surround.

In the history of hallmarking there have only ever been five other commemorative marks: one to celebrate the Silver Jubilee of King George V in 1935: one to mark the Coronation of Queen Elizabeth II in 1953, one to mark HM The Queen’s Silver Jubilee in 1977, followed by a mark in celebration of her Golden Jubilee in 2002: and then in, 2000, a Millennium Mark.

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