Feb 2025

750 Gold Hallmark Stamp (18 Carat Gold) - All You Need to Know

By StoneX Bullion

When you come across a 750 hallmark on gold, it means that the piece is made from 18-carat gold. In other words, the item is an alloy containing 75% pure gold and 25% other metals such as silver, copper, or palladium. This stamp is an internationally recognized indicator of gold purity (known as a fineness mark) that helps buyers understand the true value of their gold.

Gold is rarely used in its pure 24-carat form for jewellery because it’s too soft and prone to damage. Instead, it’s often alloyed with other metals to improve its strength and durability, and even change its colour. In this article, we’ll explore everything you need to know about the 750 gold hallmark stamp, including what it means, how gold purity is measured, and the history and process of gold hallmarking.

What does 750 mean on gold jewellery?

A 750 marking on gold jewellery is a hallmark indicating that the piece is made from 18-carat gold, which means it contains 75% pure gold and 25% other metals. This stamp helps buyers understand the gold content of pieces they’re purchasing, which is important because two items that look identical could have very different values depending on their gold purity.

In many countries, including the UK, hallmarking is legally required for gold jewellery above a certain weight. The UK Hallmarking Act of 1973 mandates that all gold items over one gram must be independently tested and stamped by an official assay office to guarantee authenticity.

Traditionally, common control marks included four symbols:

The maker’s mark or sponsor’s mark
The assay office mark
The date mark
The gold’s fineness.

The 1973 Hallmarking Act removed the need to stamp the date, and today most hallmarks only display the assay office, maker’s mark, and gold purity.

Because of its softness, 750 gold is not as commonly used for intricate jewellery designs compared to lower-purity gold (like 375 or 9-carat gold). Instead, you’ll find 750 gold used in simpler designs like wedding bands.

Colours of 750 gold

750 gold can come in different colours depending on the types of metals used in its alloy, with the three most common colours being yellow, white, and rose gold. You can also find 750 gold in other shades, like pink, green, grey, purple, blue, and even black. These shades are created by altering the alloy composition to create unique colours.

Let’s look at the different colours of 750 gold.

Yellow gold

Yellow is the most popular shade and what most people associate with gold jewellery. This colour is created by alloying gold with silver, copper, and sometimes zing. Because silver is a noble metal, like gold, it can make gold extra resistant to tarnishing and more hypoallergenic, meaning it’s unlikely to cause an allergic reaction. This makes it a great option for people with sensitive skin.

White gold

White gold has a silvery appearance, similar to platinum, and is a popular choice for modern jewellery. It’s typically alloyed with metals like platinum, palladium, or silver, with small amounts of nickel and zinc sometimes added in for extra durability. You can also find white gold with rhodium-plating that gives a more polished, bright white sheen.

Rose gold

Rose gold has a warm, reddish hue that comes from its copper alloy, with small amounts of silver sometimes included to adjust the tone. The higher the copper content in rose gold, the deeper the red shade. Because copper is more affordable than other alloying metals, rose gold tends to be a more cost-effective option of 750 gold.

750 gold colours

The table below breaks down the content of gold and other alloys in different colours of 750 gold.

	ACTUAL GOLD CONTENT	SILVER, PLATINUM, OR PALLADIUM CONTENT	COPPER CONTENT
YELLOW GOLD	75%	15%	10%
WHITE GOLD	75%	25%	0%
ROSE GOLD	75%	9.75%	22.25%
PINK GOLD	75%	5%	20%

Understanding gold purity

Gold purity can be identified using both the carat system and specific hallmarks that indicate how much pure gold is in a piece of jewellery or bullion. Understanding gold purity is essential when buying or selling gold jewellery as it can help you determine its quality and value.

Here’s a quick look at how gold purity is measured.

Read: What is Gold Bullion? Definition, Types and Investments

Carat system

The carat system expresses gold purity by dividing it into 24 parts. 24-carat gold is considered pure gold, containing at least 99.9% gold with no other metals. However, pure gold is often too soft and not ideal for everyday jewellery. For that reason, it’s alloyed with other metals to improve its strength and durability.

Different types of gold carats include:

18-carat gold (750 gold): This is made from 75% gold and is commonly used in jewellery to balance purity with durability.
14-carat gold (585 gold): This contains 58.3% gold, making it stronger and more affordable than 18-carat gold.
10-carat gold (417 gold): This is made from 41.7% gold, creating pieces that are highly durable but less valuable.

Keep Reading: What is Gold Carat?

The history of hallmarking

Hallmarking has played a vital role in gold trade and craftsmanship for centuries. The practice first dates back to the 13th century, when it was used to verify gold purity and identify who assessed the piece. In a time when gold was widely used for jewellery, coinage, and wealth preservation, hallmarking was essential for understanding the true value of gold pieces.

During the reign of Edward I of England and Louis IX of France, craft guilds controlled much of Europe’s skilled metalworking industry. To maintain quality and prevent fraud, governments introduced state-appointed assayers to independently verify gold quality. This system ensured that only genuine gold items entered the market, helping protect gold traders and uphold the reputation of goldsmiths.

In the 14th century, Edward III granted a royal charter to the Worshipful Company of Goldsmiths, recognizing their expertise and granting them authority over gold quality standards. Their headquarters, the Goldsmiths’ Hall, became the origin of the term ‘hallmark’ – the marking stamped onto gold to certify its purity.

Today, hallmarking remains a legal requirement in many countries, although regulations can vary. For example:

United Kingdom: In the UK, gold items over one gram must be hallmarked by one of four official assay offices in London, Birmingham, Edinburgh, or Sheffield.
United States: Hallmarking is less regulated in the US, and jewellery can be accompanied by documentation instead of being stamped. When gold is marked, it must contain both the gold quality and manufacturer’s trademark.
Italy: In Italy, gold jewellery is stamped with both the manufacturer’s name and a grade of quality.
China & India: There’s no mandated gold hallmarking system in China and India, resulting in greater variation of gold quality. In many cases, additional testing is needed for these products to assess true value.
Switzerland: Hallmarking is also optional in Switzerland, except in the case of gold watches.

In 1972, European countries attempted to create a unified hallmarking standard through the Vienna Convention on the Control of the Fineness and the Hallmarking of Precious Metal Objects, now renamed the Common Control Mark (CCM).

Understanding hallmarking

Although hallmarking is optional in some regions, gold jewellery is rarely sold without some form of hallmark, stamp, or engraving to indicate its purity and origin. For the untrained eye, these markings can be difficult to decipher. Let’s break down the most common hallmarks on gold jewellery.

Purity hallmark

The most important hallmark to look for is the purity grade. This tells buyers how much pure gold is in the item. Depending on the country, gold purity can be expressed in either carats or a three-digit number that represents gold content as a percentage (i.e. 750 being 75%).

Here are the most common gold purity hallmarks:

PURITY HALLMARK	PURE GOLD CONTENT IN CARATS (ct)
999.9 or 999	24ct
995	23.88ct
990	23ct
916 or 917	22ct
833	20ct
750	18ct
625	15ct
585, 583, or 575	14ct
417	10ct
375	9ct
333	8ct

Other common hallmarks

Gold jewellery can also contain additional hallmarks that specify how the piece was made. These include:

GF (Gold-Filled): Made by bonding a thick layer of gold to a base metal.
GP (Gold-Plated): Made by coating a thin layer of gold over another metal. This type of jewellery is less durable than gold-filled.
Ring Size Marking: Some rings include a small number indicating their size.

The process of hallmarking

So how does hallmarking work? In the UK, hallmarking is a highly regulated process that’s used not only for gold but other precious metals like silver and platinum. Here’s a look at how the hallmarking process works.

1. Pieces are submitted to an assay office

Jewellers and manufacturers send their pieces to one of the UK’s four official assay offices in London, Birmingham, Sheffield, or Edinburgh. Each office follows strict guidelines to verify the metal content and apply the appropriate hallmark.

2. Sampling and testing

Once the gold has been received, the jewellery undergoes testing to determine its exact metal composition. The most common methods used are:

X-ray fluorescence (XRF): A non-destructive technique that quickly analyzes metal composition.
Fire assay (cupellation): A highly accurate but destructive method that’s mostly used for gold. Here, a small sample is melted to separate the pure metal from any alloys.
ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry): It’s quite a mouthful, but ICP-OES is an advanced method used to detect metal content at trace levels.

3. The hallmark is applied

Once the metal purity is confirmed, the hallmark is applied using either laser engraving or traditional stamping (less common these days as it can distort fine jewellery).

4. Final quality assurance

After hallmarking, the item undergoes one more final inspection before being returned to the jeweler or manufacturer for sale.

How to check for gold authenticity

Gold jewellery with a 750 stamp typically indicates 75% pure gold, however in rare cases jewellery can be stamped with counterfeit hallmarks.

Here are some ways you can check for the authenticity of 750 gold:

	AUTHENTIC 750 GOLD JEWELLERY	FAKE 750 GOLD JEWELLERY
CERTIFICATION	Comes with a certification of authenticity	Lacks any form of certification or documentation
COLOUR & LUSTRE	Consistent colour and lustrous shine with a rich, golden hue	Inconsistent colour or a dull appearance due to base metals
PRICE	Priced in line with gold’s spot price	Priced suspiciously low, a red flag for potential fraud
HALLMARKS	Features a clear 750 stamp	The 750 stamp may be poorly marked, faded, or missing
WEIGHT	Feels heavy and solid due to gold’s density	Feels lighter than expected
MAGNET TEST	Won’t be attracted to a magnet, since gold is not magnetic	May be attracted to a magnet, suggesting the presence of non-gold metals
SELLER REPUTATION	Sold by reputable dealers or stores with a demonstrated history of excellence	Found through unknown or unreliable sources with unclear backgrounds
SOUND TEST	Produces a soft, long, high-pitched ring when dropped	May create a sharp, short sound

See: How To Spot Fake Gold Coins and Avoid Fraud

Buy authentic, investment-grade gold

If you’re looking for practical jewellery that can be worn everyday, 750 gold is an excellent choice. But if you’re thinking about gold as an investment to preserve and grow your wealth, you might want to look at 24-carat pure gold.

While 24-carat gold isn't commonly used for jewellery due to its soft malleability, it can be worn in the form of wearable bullion. At StoneX Bullion, we stock a range of beautiful, high-purity gold bullion jewellery including gold chains, pendants, and bracelets. This collection is made from high-quality, investment-grade gold carefully crafted for timeless value. Browse our range of wearable gold bullion jewellery now.