Often times we witness jewellery pieces have some marks or stamps on them which we are completely unaware of and do not even ponder, but there is always a reason behind such marks and stamps and one should be completely aware of what they are purchasing.

This article aims to highlight the meaning of some of the stamps found on jewellery pieces.

What Does SU Stamp on Jewellery Mean?

The stamp SU means silver unlimited. If you are wearing a piece of jewellery that contains the stamp of SU then it means that the jewellery is made of pure sterling silver. Sterling silver is an alloy of silver which contains 92.5 % of silver and 7.5 % of other metals making it a high-quality choice for jewellery pieces and wearables.

Jewellery made of sterling silver is timeless, durable, and will last a lifetime if taken care of.

The sterling silver has a standard minimum millesimal fineness of 925. The concept behind the 925 written on jewellery pieces is that out of the 1000 sheets used in the making, 925 are sheets are pure silver while the rest of the 75 sheets comprise other metals.

What Does SU Ch Mean?

As explained earlier that SU means silver unlimited and CH means plated metal, so SU ch labelled jeweller is actually silver plated jewellery which is 925 parts per 1000 parts pure silver. This means that the jewellery is 92.5% pure silver.

What Does CH Mean?

CH refers to ‘chapa’ plated metal in Spanish when it is stamped on a piece of jewellery. This means that the jewellery is plated with metal and not in its original form. If you find ch written on a piece of silver jewellery then it means that the jewellery is silver plated.

It is important to identify the metal that is used for plating. Often times such symbols and stamps could also be makers mark, therefore one needs to look for the stamp of the metal which is followed by a CH mark. For instance, SU means silver unlimited, so the ch following it means that the piece is plated.


To wrap it all up, SU means sterling silver unlimited which is stamped on your rings if they’re made of pure silver. Moreover, if you find a ‘ch’ stamp on your ring it refers to chapa which means that the jewellery is metal plated and not in its original form.

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