About Jewelry Hallmarking

About the Dublin Assay Office

The Dublin Assay Office was established in 1637. One of many Assay Offices found throughout Europe and the globe, the Dublin Office was established as a non-affiliated organization to determine the quality of Irish jewelry.

The Dublin Assay Office is located inside of the stunning Dublin Castle in the heart of Dublin Ireland. 

Anatomy of a Hallmark

A full hallmark contains five pieces; the sponsor’s mark, standard mark, fineness mark, Assay office mark, and the date letter. Each mark is further explained below.

anatomy of a hallmark, hallmarked jewelry


Sponsor's Mark

The sponsor's mark brands the item as coming from a particular maker or retailer.

All sponsors have registered with the Assay Office in Dublin. For example, this Boru ring features the Boru logo on the inside rim.

Standard Mark 

Gold Stamp:

In Ireland, stamping pieces with a mark like 14K is not standard. In fact, if the piece comes from Ireland, a 14K stamp might indicate a fraud.

For Irish gold jewelry, it is standard that the piece is marked with the percentage of gold compared to other metal alloys. This is essentially what 14K means too; the jewelry piece is 14 parts gold compared to 10 parts metal alloys. In the US, 24K represents pure gold.

Gold jewelry is marked with the actual percentages, rather than the amount of karats. For example, if you divide 14K by 24K you learn that the jewelry is 58.5% gold. Rather than making you do the math, the Assay Office stamps 585 onto the gold jewelry for you! The mark of 750 translates to 18K gold and 916 is 22K.

Silver Stamp:

Sterling silver jewelry is marked with 925. Similar to gold hallmarking, 925
represents the percentage of pure silver to other metal alloys. In order for an item to be considered sterling silver, it must be created from 92.5% pure silver.  

Assay Office & Fineness Marks

Every Assay Office has a unique mark that clarifies where the jewelry piece has been stamped. This mark is also pressed into the jewelry. The mark of Dublin’s Assay Office is a seated woman leaning on a harp, a staff of grain in one of her hands (Pictured Right). 

To assure that the jewelry is genuine, a Ireland’s fineness stamp is also stamped into the jewelry. For Ireland, the fineness stamp is an Irish harp with a crown over it (Pictured Left). 

Date Letter Mark:

The date the item was hallmarked is represented by a letter. R, S, and T are the symbols of 2016, 2017, and 2018, respectively. The date letter is optional, and not necessary for a legitimate piece of gold or silver jewelry.

Where to find a hallmark stamp on your jewelry: 

Often, hallmarks are small and require a magnifying glass or jewelers examination tool to find.

For rings, hallmark is found on the inside of the band.  

For earrings, the stamp can often be found on back of the earring or on the stud. Dangle earring hallmarks can be difficult to find, but are likely located on the back of the earring’s design.

Necklace feature the mark on the back if possible, likely somewhere on the design.

Biddy Brands & Hallmarks

The following brands stocked by Biddy Murphy all have hallmarked items: Solvar, Fado, Boru, and JMH Jewellry. Each of these brands crafts items with genuine gold and sterling silver. After an item is created, it is sent to the Assay Office in Dublin Castle.