Irish Hallmarks on Celtic Jewelry Explained…

On a piece of Irish jewelry made of gold, silver, or platinum, an Irish Hallmark should always appear. This stamp, which details the “fineness” of the piece, is a guarantee of quality.

From sterling silver, with its distinctive 925 designation, to 14k gold stamped with 585, you can determine a lot about rings, pendants, and earrings, simply by examining their individual Hallmarks…

On every piece we sell, we feature two stamps; one is an assay (stamp) from Dublin Castle. When you see this mark, you will know that your piece has been crafted in Ireland itself and inspected at the Castle’s historic Assay Office.

The second stamp is the Irish Hallmark – it will tell you about the precious metals used in your piece…the karat and purity, as well as the year when it was produced, can all be ascertained by the markings on your jewelry design…

The History Of Irish Hallmarks

In 1637, the Assay Office in Dublin Castle opened its doors…it was created to inspect all silver and gold in the Emerald Isle.

By stamping gold and silver with a special maker’s mark, it was possible to recognize which company created the piece.

A special symbol, in the form of a crowned harp, was used to denote “fineness” in 22 karat gold and sterling silver. Sterling must contain a ratio of 925 parts finest silver per 1000.

This is the reason why you will find the number 925 stamped on sterling silver Celtic jewelry and other pieces (such as flatware) crafted from this precious metal.

By the early seventeenth century, a special system was invented to record the year when each piece of gold or silver was created. This extra assay was stamped alongside the markings discussed above.

Known as the date letter, this letter is adjusted each year on New Year’s Day.

Still another important mark appeared in 1730 – the Hibernia stamp was added to prove that the correct amount of duty was paid on pieces created at that time, or afterwards.

Until the Irish Free State was established in the 1920’s, pieces assayed in Ireland were under the same laws as Scotland and England. All three countries employed the same methods when hallmarking gold and silver. In time, Ireland was free to follow its own laws, but the process remains very similar to its original format.

Today’s Common Markings

Gold, silver, and platinum appear in different karats and purities on today’s Irish jewelry designs:

Gold –
9 karat is assayed with the number 375.

10 karat is assayed with the number 417.

14 karat is assayed with the number 585.

18 karat is assayed with the number 750.

20 karat is assayed with the number 833.

22 karat is assayed with the number 916.

Very high purity in gold is marked with the highest assays – 990 or 999.


There are four different assays for silver: 800, 925 (sterling silver), 958.4, and 999.


There are also four assays for this precious metal: they are 850, 900, 950, and 999.

Today’s Irish Jewelry Meets The Highest Standards Of Quality…

Today’s Irish jewelry designer honor the old traditions by crafting handmade wedding rings, engagement rings, and so much more…

By using ancient Celtic symbols, such as Trinity Knots, spirals, and shamrocks to adorn rings, pendants, and earrings, the artisans of Ireland combine tradition with modern style elements. This melding of past and present creates uniqueness and beauty that will be treasured for a lifetime.

If you’re interested in stunning Irish and Celtic design with heirloom quality, such as this gorgeous diamond Celtic engagement ring, please visit our online Irish jewelry store to browse our wide selection of beautiful pieces…

For more information on the different alloy content for the metal types, visit or other Irish Hallmarks page.

7 thoughts on “Irish Hallmarks on Celtic Jewelry Explained…

  1. I have a pendant (dove with olive branch) which has three markings on the back: JAC, “Made in Ireland” and “ISJ??K” Is it possible to tell who made this or when? My questions marks (??) denote two marks I cannot identify-possibly the harp and a designator of the item being silver…? thanks so much! mary

  2. Hi Mary,

    Jewelry that is made in Ireland is required to be stamped by the Dublin Assay Office, located on the grounds of Dublin Castle.

    The stamping guarantees the quality of the metal. I would hazard a guess that the 2 questions marks (??) before the K denote the metal quality e.g. 10k or 14k.

    I also know that sometimes the manufacturer stamp their initials on their pieces. I would say the ISJ could be the manufacturers initials. Unfortunately, I don’t have know what manufacturer these initials might stand for.

    Sorry I couldn’t be more helpful.

  3. I inherited earrings believed to be from Ireland, and believed to be made prior to 1904.

    There are carvings in the earrings,

    375 (( )) followed by a circle with a cross on top of the circle, but, it’s hard to see.

    Between the (( )) is an anchor on it’s side.

    The last figure resembles a circle with a cross on top of the circle,
    and the final letters look like CP.

    There may be a 9 at the very beginning of the symbols.

    ALL HELP WELCOMED, thank you, this is very important family heirloom.

    Even if you should stumble across this question years after it’s posted, feel free to offer an answer. thank you.

  4. Hi Jean. The number 375 is used by the Assay Master to indicate that the metal is 9ct gold. This might also explain the number 9 that you’ve seeing. I don’t recognize the other symbols and letters that you mentioned, so these could be the manufacturers initials and logo. I hope this helps.

  5. Hi, I have a silver small harp broch, which belonged to my grandfather Peter Johnstone who player for Glasgow Celtic between 1909 and 1916. He played for Scotland against Ireland and on his football medal appears a small Irish harp – he also brought back from Ireland a small silver Irish harp with shamrock stones. We’re thinking he may have bought this for his wife after the match in Ireland but its just odd that there is a harp on his Scottish medal. The number K386412 appears on the bottom of the broch and there is a hallmark on the side, but I can’t make it out. Can anyone shed any light on this. thanks.

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