The Final Seal of Approval - The Irish Assay Office

When you get a piece back from casting, it looks like this - a raw cast with sprues on (the bits of metal that poke out).

We’re fortunate that Ireland guarantees the purity of all precious metals produced and sold commercially in this country, which chiefly means that the consumer is protected, and genuine jewellers are certified.

To “assay” means to test a metal or ore to determine its ingredients and quality. That is the core function of the Assay Office.

Nestled away on the grounds of our iconic Dublin Castle, to be assayed means undertaking a rigorous process that has been in existence since the 17th century.

As a jeweller, first you have to register with the office and be assessed. Once you pass the registration process you are issued with an official certification. As part of the process you need to establish your Makers Mark, with is a unique symbol or stamp that exists only for you. When your pieces are being assayed by the office, the stamp is applied on approval of the metal.

The Irish Hallmarks come in three parts. Alongside each jewellers unique Makers Mark, The Irish Hallmark includes the Hibernia mark which is the stamp of the Dublin Assay office showing a seated lady, along with digits guaranteeing the precious metal content - this stamp includes a mark which references the metal and its fineness, sometimes referred to as the purity mark.

For example, our solid gold pieces are stamped on approval with the "LL" Makers Mark, the Assay Office Mark, and the Metal and Fineness Mark, which is the "9", for 9 carat gold, and "325" which tells you the precious metal content in gold expressed in parts per thousand. Our solid sterling silver prices are hallmarked in the exact same way, with the exception of the Metal and Fineness Mark, which is "925" which tells you the precious metal content in silver expressed in parts per thousand.

Every single By Leahy piece is deep laser marked. This means that, even if it’s 100 years down the line and a By Leahy piece is being passed through the generations, that piece can be uniquely traced back to where and when it was stamped, meaning it’s lineage and quality are guaranteed.