<P> The most elaborate, but totally destructive, assay method is the fire assay, or cupellation . As applied to gold bearing metallics, as in hallmark assaying, it is also known as cupellation and can have an accuracy of 1 part in 10,000 . In this process the article is melted, the alloys separated and constituents weighed . Since this method is totally destructive, when this method is employed for the assay of jewelry, it is done under the guise of random or selective sampling . For example, if a single manufacturer deposits a lot of rings or watch cases, while most are assayed using the non-destructive methods a few pieces from the lot are randomly selected for fire assay . </P> <P> There are methods of assay noted above which are more properly suited for finished goods while other methods are suitable for use on raw materials before artistic workmanship has begun . Raw precious metals (bullion or metal stock) are assayed by the following methods: silver is assayed by titration, gold is assayed by cupellation and platinum is assayed by ICP OES spectrometry . </P>

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