Gold is the heart of fine jewellery, but a few words do a lot of quiet work, solid, karat, plated, white, and it pays to know what they mean. This guide is the overview: what solid gold actually is, how purity and colour work, where platinum fits, and how to look after it. Each section links to a fuller guide if you want to go deeper.
Solid gold is gold all the way through, mixed with other metals to set its strength and colour. Its purity is measured in Karat, shown as 9K, 10K, 14K or 18K, and its colour, yellow, white or rose, comes from the metals it is mixed with. Solid gold holds its colour and lasts for life, which is what separates it from plated jewellery that wears through over time.
What is solid gold?
Solid gold means the whole piece is made of a gold alloy, so the gold runs all the way through rather than sitting as a thin layer on the surface. Pure gold is too soft to wear every day, so it is mixed with harder metals to make it durable, and that mix is still solid gold. This is the important distinction in jewellery: solid gold has nothing to wear through, so it keeps its colour and lasts a lifetime, while plated pieces carry only a fine skin of gold over a cheaper base metal that eventually wears away. Our guide to solid gold vs plated, vermeil and gold-filled explains exactly how each type is made and how long each one lasts.
Gold purity: 9K, 10K, 14K and 18K
Gold purity is measured in Karat, written with a capital K, and you will see it as 9K, 10K, 14K or 18K, also written 9ct, 10ct, 14ct and 18ct in New Zealand. The number is how many parts out of 24 are pure gold, so 18K is 75 percent gold, 14K is just under 60 percent, 10K around 42 percent, and 9K is 37.5 percent, with the rest made up of stronger metals. Higher karat means a richer colour and more pure gold, but a slightly softer metal, while lower karat is harder and more affordable. For most everyday pieces 9K, 10K and 14K strike a good balance of durability and value, while 18K is chosen for its deeper colour and higher gold content. Our guide to 9K, 14K and 18K gold covers the trade-offs in full.
Yellow, white and rose gold
The colour of gold comes from the metals it is mixed with, not from the amount of gold, so at the same karat, yellow, white and rose gold all hold the same amount of pure gold. Yellow gold is mixed with copper and silver for its classic warmth, rose gold takes more copper for its pink blush, and white gold is mixed with white metals and then finished to a bright silvery white. Which suits you is mostly taste, with a light nod to skin tone, and our guide to yellow, white and rose gold helps you choose.
White gold and rhodium
White gold deserves a word of its own, because it is finished differently from the others. The white gold alloy has a faintly warm tone on its own, so it is usually plated with a thin layer of rhodium, a bright white metal from the platinum family, to give it the crisp white finish people expect. The gold underneath is solid and permanent, but that surface finish gently wears with time and is simply refreshed with occasional replating. Our guide to white gold and rhodium plating explains what to expect and why.
Where platinum fits
Platinum is the other white metal used in fine jewellery, and it is naturally white all the way through, so it never needs plating to stay that colour. It is denser and more hard-wearing than gold, and more expensive for the same piece. White gold gives a very similar look for less, with a little upkeep, while platinum is the low-maintenance, premium choice. Our guide to platinum vs gold compares them side by side.
Caring for gold
Solid gold asks very little. A soak in warm water with a little mild dish soap, a gentle brush and a soft cloth keeps it bright, and keeping it away from chlorine and harsh chemicals keeps it that way for years. Our guide to caring for gold jewellery has the simple routine.
How to choose the right gold for you
With the pieces above understood, choosing comes down to three easy decisions.
Choose your karat for how the piece will be worn and your budget, with 9K, 10K and 14K best for hard everyday wear and 18K for a richer colour. Choose your colour, yellow, white or rose, on what you love and what suits your skin. And choose solid gold over plated for anything you want to keep, because only solid gold holds its colour and lasts a lifetime.
From here you can follow any of the guides above, or simply explore the pieces themselves. Everything at Noble is solid gold, across earrings, bracelets, necklaces and pendants, rings and men's.
