A Complete Guide to Jewelry Stamps and What They Mean

What do 750 and 925 mean on jewellery? A 750 gold fineness mark indicates 75% gold, commonly called 18K. A 925 silver mark indicates 92.5% silver, known as sterling silver. These are clues to composition; a mark alone does not authenticate a piece.

This guide explains common gold, silver and plating marks, and what to check when choosing jewellery. Marking practices vary by country, age and manufacturer.

يشير ختم 750 عادةً إلى ذهب عيار 18، وختم 925 إلى فضة إسترلينية بنسبة 92.5%. لكن الختم وحده لا يكفي لإثبات الأصالة، كما أن عبارة «مطلي بالذهب عيار 18» لا تعني أن القطعة مصنوعة من الذهب عيار 18 بالكامل.

Gold stamps: karats and fineness numbers

Karats express gold content in 24 parts. Fineness numbers express it in parts per thousand. The number 18 in 18K means 18 out of 24 parts gold, not 18%.

• 9K / 375: 37.5% gold.
• 10K / 417: approximately 41.7% gold.
• 14K / 585: commonly marked as 58.5% gold.
• 18K / 750: 75% gold.
• 22K / 916: approximately 91.6% gold.
• 999: 99.9% gold, associated with fine gold.

Pure gold is soft; other metals are added to gold alloys to alter strength and colour. A higher karat number describes gold content, rather than guaranteeing that a design suits every kind of wear.

Silver marks: 925, sterling and other standards

925, .925 and sterling commonly identify sterling silver: 92.5% silver combined with other metals. Other fineness marks include 800 (80%), 958 (95.8%) and 999 (99.9%). Interpret a number together with the metal description and other marks.

A 925 mark on gold-coloured jewellery may refer to a silver base with gold plating. It does not mean solid gold.

Gold-plated, gold-filled and silver-plated marks

• GP: gold plated — a surface layer of gold over another metal.
• GEP: gold electroplated.
• GF: gold filled — a mechanically bonded gold-alloy layer over a base metal; this is a different construction from ordinary electroplating.
• RGP: rolled gold plate; read the accompanying composition information.
• SP: silver plated.
• EP: electroplated; the accompanying description should identify the coating metal.

A description such as 18K gold-plated brass means that the surface coating is 18K gold and the underlying metal is brass. It does not mean that the entire piece is 18K gold. The coating can wear with use; thickness, care and wear conditions affect its lifespan.

Platinum and stainless-steel marks

Pt950 and Plat950 indicate 95% platinum; Pt900 indicates 90%. A bare number needs context because different metals can use similar fineness numbers.

Stainless Steel and 316L describe steel or its grade. They are not precious-metal purity marks. Stainless steel can contain nickel, so a steel mark alone is not a guarantee against skin sensitivity.

Is a stamp the same as an official hallmark?

No. A simple fineness stamp is not necessarily an independently verified hallmark. For example, a full UK hallmark includes a sponsor's mark, a fineness mark and an assay-office mark. Other countries have different systems. Unmarked jewellery is not automatically fake, and a stamped piece is not automatically genuine.

What to check before buying

• Ask for the exact base metal and any surface coating.
• Confirm whether “18K” refers to the whole metal alloy or only the plating.
• Read the product description and care instructions alongside the mark.
• For a valuable piece or an uncertain mark, ask a qualified jeweller or assay office about appropriate testing.

Choose by material at Miniz

Explore our 18K gold jewellery collection or browse personalised jewellery. Check the specific material stated for each piece before ordering. Our jewellery care guide explains how to look after your pieces.

اكتشفوا مجموعة مجوهرات الذهب عيار 18 أو المجوهرات المخصّصة. تأكّدوا من الخامة المذكورة في وصف كل قطعة، وراجعوا دليل العناية بالمجوهرات.

Further reading

For independent information, see Birmingham Assay Office's guide to UK hallmarks and the FTC Jewelry Guides.

---