The Learning Table | Different Metal Carats


For us, sharing our insight into and experiences of the jewellery industry comes from a genuine passion for our craft, and a joy in sharing this knowledge with others. 

This is why we created our journal series, The Learning Table. Our bespoke team often sit down together at the "creative table" in the office to discuss design ideas, current projects and share their thoughts and skills with each other. Now, it’s your turn to have a seat at the table as the team share what they have learnt over the years in and amongst the ever evolving and fascinating world of jewellery.

This week (over a coffee of course!) the bespoke team explained the answer to a question we are often asked by our clients – what is the difference between 9ct, 14ct and 18ct gold? Without delving too deep into the science of metals and alloys, our bespoke team have explained the differences to help you make the best choice for your next NMJ piece, and also shared with us whether there is a noticeable difference in colour between the carats. Welcome to this edition of The Learning Table… 

Let’s start with the difference between 9ct, 14ct and 18ct gold:

The difference between 9ct, 14ct and 18ct gold is the precious metal content. 9ct gold contains 37.5% pure gold, 14ct contains 58.5% pure gold and 18ct gold contains 75% pure gold. The remainder is a mix of various metals, depending on whether it is a yellow, rose or white gold piece.

As 18ct has the highest gold content, and gold is a malleable material, pieces created in this carat are ideally suited for everyday wear, as their shape will adjust to suit you, which is beneficial for jewellery intended for a lifetime of wear. A great example of this can be seen in 18ct rings that are worn over a long period of time which turn ovular in shape, rather than round, to mirror the shape of the finger. This is the natural behaviour of the material and its interaction with our bodies.

Through the hand-manufacturing process, 18ct gold goes through a work-hardening process. This means that the metal is worked from its raw form, all the way through to the final piece. The time, methods and use of specialised tools through this process gives the metal a great amount of strength and durability, which is perfectly balanced with the malleable nature of gold and ensures guaranteed structural integrity.

At NMJ, we always recommend 18ct gold for all precious pieces such as engagement rings and wedding bands. It is also a great option for people who find they have reactions to base metals, such as the copper used in yellow and rose gold alloys, as 18ct has a higher pure gold content making it more suitable for reactive skin.

14ct gold has a pure gold content of 58.5% and is commonly used in jewellery manufacturing in North America and Europe, and so we offer it as an alternative to 18ct for our customers.

In general, 18ct gold is the longer lasting, more durable choice, however 9ct gold can still be a great option for some Jewellery pieces. 9ct gold is commonly used for fine pieces of jewellery that are typically designed for casual wear. Our seasonal collection fashion pieces, or statement pieces are typically crafted in 9ct gold. The reason for this is that these are generally our finest pieces, and where 18ct is flexible, 9ct gold is more rigid and holds its shape better as it has the lowest pure gold content – making it great for casual wear while also bringing it into a more accessible price point. We choose to craft all of our collection pieces in solid 9 carat gold rather than gold plated, gold filled or gold vermeil as the quality and longevity is incomparable.  

How can I find out what carat finish my piece is?

The carat finish can be identified by a small stamp (hallmark) located on the gold, typically in a discreet spot such as the inside of a band, the clasp of a necklace or bracelet or the post or butterfly of your earrings.

9ct - ‘9ct’, ‘9k’ or ‘375’

14ct – ‘14ct’, ‘14k’ or ‘585’

18ct – ‘18ct’, ‘18k’ or ‘750’


What about colour? Do the different carat finishes affect the metal colour?

Put simply, the higher the gold content, the richer the colour and warmer the tone, particularly for yellow and rose gold. However, only when side-by-side are these differences really noticeable to the eye, and they are generally quite subtle so don’t affect the overall aesthetic of your piece of jewellery. The thinner or smaller your piece, the less noticeable the colour difference will be.


Yellow Gold 

9ct yellow gold appears as a subtle, pale yellow while higher carats, such as 18ct in particular, present a richer, more vibrant golden tone. As a 9 carat alloy is more diluted with other metals, there can be some minor colour evolution or tarnishing over time, whereas 18 carat has a more stable finish. 

Rose Gold

9ct rose gold is a soft pink, while 14ct and 18ct are a much warmer, peach-toned colour. Our 18 carat rose gold alloy is always popular for its soft warmth and lack of coppery undertone. 

White Gold

As an industry standard, most white gold is rhodium plated. This means you’re not actually seeing the natural colour of the metal as it is plated in a thin layer of rhodium, which is a naturally white metal, so that the stunning bright silver-colour appears consistent no matter the carat. This finish is generally reapplied annually when rings are serviced to maintain the colour.  

If you’re opting for an un-plated white gold, the natural colour of the metal in 9ct is slightly darker than sterling silver. You will find that the 9ct looks silvery, and then the higher the carat the darker the grey tone becomes, resulting in more of a steely grey with a slight warmth, making it a popular choice for mens wedding rings.

What about Sterling Silver?

Sterling silver is the industry standard silver alloy used to make jewellery, and here at NMJ we use it strictly for fashion pieces. While the metal itself is not appropriate for lifetime wear, it is a great entry level metal for people who like a white gold look, but don’t want to invest in the higher value metal as the intention of the piece is more for casual wear. Sterling silver is aesthetically similar to rhodium-plated white gold, however it will oxidise when exposed to oxygen, chemicals and the natural oils from your skin and therefore requires more upkeep with regular polishing and cleaning.

Sterling silver is also a very soft metal and is very malleable, so we don’t recommend this alloy for men’s wedding rings. 

At NMJ our sterling silver is nickel free and so suitable for people with nickel allergies. 

PC: @tealily