The yellow colour of gold is caused by absorbing violet and blue light, but reflecting yellow and red light. Pure gold is combined or 'alloyed' with other metals to add strength, and hardness.

The amount and type of other materials (alloys) added determines the final carat (gold content) of the gold alloy.

18k gold is composed of 75% gold, which is alloyed with other metals, normally copper to make it strong enough for everyday use.

The chemical symbol of gold is Au. This symbol comes from the Latin word "aurum," which means shining dawn. Gold’s atomic number is 79 on the periodic table.

Gold is made through processes that happen in some of the most violent and energetic events in the universe.

Gold is not formed in normal stellar fusion (like how stars make helium from hydrogen). Instead, it’s created during cataclysmic stellar events such as Neutron Star Mergers

When two neutron stars collide, they produce an explosion called a kilonova. These collisions release enormous amounts of energy and free neutrons.

Neutron stars collide when two of them are in a binary system, orbiting each other and gradually spiral inward due to the emission of gravitational waves.

Binary neutron stars are rare, but not impossibly so and their mergers are even rarer. Only 20 confirmed BNS systems have been found in our entire galaxy.

In this environment, rapid neutron capture (r-process) occurs, building up heavy elements like gold, platinum, and uranium. Recent observations (like the 2017 detection of gravitational waves from a neutron star merger) confirmed this as a major source of cosmic gold.

Of course, this begs the question, what is a Neutron Star? In short, a neutron star is formed when a star collapses, they are small, approximately 20 KM wide but incredibly dense.

In short, That means you're squeezing more than a Sun's worth of mass into a sphere the size of a city… This makes neutron stars some of the densest objects in the universe. A sugar-cube-sized amount of neutron star material would weigh about a billion tons on Earth!

After being forged in space, gold atoms are blasted into interstellar space. Over billions of years, some of this material ends up in new stars, planets, and asteroids.

All the gold on Earth, including the gold in your jewellery, likely came from collisions of dead stars billions of years ago, before the Earth even existed.

It is at least 4.6 billion years old, and much of it could be billions of years older, formed in the ancient deaths of stars that long predated our Sun. When you wear gold, you're literally wearing the product of cosmic violence from long before the solar system was born.

A neutron star

What a neutron star collision might look like to the eye

The principal difference is the precious metal content. 9 carat gold contains 37.5% pure gold. 18 carat gold contains 75% pure gold.

The remainder is an alloy of various metals, which may include copper, zinc, silver, palladium or platinum, depending on its intended colour - ie yellow, rose or white.

9 carat is harder than 18 carat gold, it resists scratching well and was traditionally used for such items as watch cases

A 18 carat gold item will generally be more expensive than its equivalent in 9 carat gold as it contains double the amount of pure gold.

it is strong, beautiful, durable and does not tarnish, corrode or react with the skin.

24 carat gold is gold in its purest form and consists of 99.9% gold. It is naturally yellow and extremely valuable, but also soft and malleable, so not usually used to make fine jewellery.

See our guide to UK Hallmarking here.

White gold is an alloy made by mixing pure yellow gold with white-coloured metals (like palladium, nickel, or silver) to give it a silvery-white appearance. It’s popular as a modern alternative to platinum.

Gold is naturally yellow, so the white metals dilute the yellow tone, giving it a pale colour. However, white gold is not perfectly white on its own. That’s why most white gold pieces are rhodium-plated.

Rhodium is a rare and precious element that can be 10 to 25 times more expensive than gold. Rhodium is a member of the platinum group of metals and is silver-hued, highly reflective and does not tarnish or corrode. It is harder than gold and is highly durable.

See notes on Rhodium below.

Rose gold is made by alloying pure gold with copper (and sometimes a bit of silver). This process changes both the colour and physical properties of the gold, making it stronger and giving it its distinctive pinkish hue.

Rose gold is not found naturally; it’s created through alloying: Pure gold (24k) – soft and yellow in colour. Copper – provides strength and the reddish colour. Silver (optional) – used to soften the red tone and improve malleability.

Rose gold originated in early 19th-century Russia, where it was known as "Russian gold" and popularised by famed jeweller Carl Fabergé in his Fabergé Eggs.

Rose gold is stronger and more scratch-resistant than yellow or white gold of the same karat due to copper. Over time, rose gold may darken slightly or develop a warm patina, which enhances its vintage look.

Sterling silver is a high-quality silver alloy composed of: 92.5% pure silver and 7.5% other metals, usually copper.

Sometimes modified alloys may substitute copper with elements like germanium, zinc, platinum, or silicon to enhance tarnish resistance or hardness (e.g., Argentium® Silver).

The reason pure silver isn’t typically used on its own is because it's too soft for most functional items. Adding a small percentage of another metal—usually copper—increases its strength and durability without significantly affecting its appearance.

Silver tarnishes over time as it reacts with sulphur containing substances in the air, forming a compound called silver sulphide (Ag₂S). This reaction is what causes the surface of silver to darken or turn black over time.

Sources of sulphur:
Air pollution (especially near industrial areas)

Household items (like rubber bands, wool, latex, and some foods—eggs, onions, garlic)

Skin oils and sweat (which can contain sulphur compounds)

We recommend using a commercial silver polish with a soft cloth to remove the patina - although a lot of clients prefer the "aged" look.

Gold vermeil, or just vermeil, is a term used to refer to jewellery or other items made of silver and coated with gold. The word “vermeil” comes from the French and is pronounced “ver-may.” Vermeil jewellery is made by first creating the base of the item in silver and then plating it with a layer of gold. This method is called electrolysis.

The essential difference between vermeil and gold-plated jewellery is that vermeil items have a base made of silver, whereas plated and filled pieces can be made with a variety of base metals such as bronze. For this reason, vermeil jewellery is generally more valuable than comparable gold-plated items.

See Gold Plating

Rhodium is a rare and precious element that can be 10 to 25 times more expensive than gold. Rhodium is a member of the platinum group of metals and is silver-hued, highly reflective and does not tarnish or corrode. It is harder than gold and is highly durable.

However, rhodium is a very brittle metal and is not easily shaped or formed. As a result, pure rhodium cannot be made into jewellery. On its own it can easily crack and break somewhat like glass. But when used to plate other jewellery, rhodium enhances the durability of the metal.

Rhodium is Applied using an electroplating process. For a piece of jewellery to be plated, it must first be thoroughly cleaned to remove all contaminants. If there is any dirt on the piece, the plating will not hold.

Distilled water, steam cleaning and electro cleaning are some ways that the item is cleaned before it is dipped into the rhodium solution. A positive electrical charge is then used to fuse the rhodium onto the base metal.

Rhodium plating wears off over time and will need to be re-plated. Typically, a ring would need to be re-plated once every 12 to 18 months, but this can vary depending on the wear and tear the piece sustains as well as the thickness of the plating and the colour of the base metal.

Can I rhodium plate a yellow gold piece?
Yes. Rhodium plating can be used on yellow gold to change its colour to white. However, bear in mind that as the plating starts to wear off, the yellow colour will start to bleed through. This will result in a piece of jewellery that looks discoloured or yellow-tinted. To avoid that, the piece may require re-plating more frequently.

Is rhodium plated jewellery safe to wear?
Yes, it is. Because rhodium plating is hypoallergenic, you won’t get skin reactions by wearing rhodium plated jewellery. This is because rhodium does not contain any allergens such as nickel. In fact if you have a piece of jewellery that is causing you skin reactions, rhodium plating the piece can eliminate this problem.

Will rhodium plating affect gemstones?
Some softer gemstones such as peridot, pearls, opals, topaz, turquoise, coral and treated or heavily included rubies and emeralds can be damaged during the process. These gemstones, and many others, are not able to cope with the sulphuric acids and heat in the electroplating solutions and their surfaces can be damaged, becoming spotty and studded.

Diamonds and hard gemstones like sapphires and rubies are hardy enough to withstand rhodium plating. They don’t have to be removed when plating the piece of jewellery and don’t get damaged by the process.

One of the world's rarest metals, palladium makes for a band that's high in quality and, relatively speaking, lower in price than other high-quality metals. With the increase in the price of gold and platinum, palladium is one of the best choices for those with a lower budget who don't want to sacrifice quality or beauty.

The metal is similar to platinum in that it's hypo-allergenic and keeps well over time.

it's strong and never tarnishes over the years. It doesn't require plating or other metals for protection - it will stay white without regular maintenance and care. While it's in the same group as platinum and looks very similar, it's much lighter than its sister metal.

It was officially recognised as a precious metal in 2010, and it's now a legal requirement that any palladium ring that weighs more than 1 gram is hallmarked. It's even been said that palladium is rarer than gold.

Pure platinum is a lustrous, ductile, and malleable, silver-white metal Platinum is a chemical element with symbol Pt and atomic number 78. It is a dense, malleable, ductile, precious, grey - white transition metal. Its name is derived from the Spanish term platina, which is literally translated into "little silver".

Platinum 950 means that 95 per cent of the weight is made up of fine platinum. Platinum 950/Cobalt is the very best alloy for platinum casting. It is very strong and has excellent casting properties. With this alloy it is possible to cast pieces of considerable detail and finesse.

Whilst gold contains a combination of metals, platinum's purity makes it naturally hypoallergenic and non reactive, ideal for those with skin sensitivities. Denser than gold and twice as dense than silver, it can be quite heavy but this is a favourable quality, especially for men.

Despite its durability, like most metals, it does tend to wear a little over time and will scratch if it comes into contact with stronger materials, such as diamonds or steel. Unlike gold, platinum doesn't chip away but instead the scratches are seen as indentations that can be easily re-polished and brought to a high white shine.

Platinum is created in the same process as gold - see above