The Dublin Assay Office
The Dublin Assay Office located in Dublin Castle was formed in 1637 to ensure that all jewelry of precious metals sold in Ireland be assayed and stamped with an official hallmark. With the distinctive Irish hallmark and assay, you can be assured that you are getting the very best quality of jewelry.
The Hallmark & Assay Stamp
The official hallmark was the traditional letter symbol for the year the piece was crafted.
Gold is the ultimate precious metal and its purity is always measured in carats. The purest gold is 24 carats which is very soft. Gold is mixed with other metals and the carats are determined. Thus, 14kt gold is 14/24 gold mixed with 10/24 other metals.
Sterling silver is the purest form of silver you will find in jewelry. Sterling silver is a silver of a standard of 925 parts of fine silver in each 1000.
An assay is a test performed on precious metals such as gold, silver or platinum to determine its purity. This process is performed by scraping the metal, treating it with a trace of acid and comparing it against standard marks. After determining the purity, the piece is stamped accordingly, i.e. 10kt, 14kt. The fineness mark, the crowned harp, was applied to 22kt gold and sterling silver.
The actual Assay Stamp is the small series of boxes that you will see on the inside of your ring. See the example below.