Popular Metal Alloys and Metal Plating in Precious Jewellery

The use of alloys is an integral part of jewellery making, since precious metals, notably the most popular variants: gold, silver and platinum in their pure form are almost impossible to be made and shaped in a way that fits the demands of fine jewellery that must stand the test of durability, luxury and comfort. The challenge for jewellery makers lies in maintaining the inherent value that is attached to the precious metal in its original form, whilst enhancing its metallic character that can meet the demands of modern wearers. Which in addition to beauty, and personal taste, must also factor in the elements of cost and health. As we shall see, fine jewellery buying is an immensely personal decision, and that is meant to stay with you for a long time, thus getting it right requires a degree of attention. Even if the decision is to go with cheaper plated metal jewellery, there are important factors you need to keep in mind.

The Meaning of Metal Alloying

Before we explain the types and the differences between the top metal alloys that are used in the making of fine jewellery, as a start it is best to understand what is meant by the term alloy, or the process of alloying. The basic understanding is that to form an alloy, is to combine two or metals together to form a new type of metal that contains attributes of those elements that had gone into making it; with features (like the colour) of the metal that is dominant being the most notable in the final product. Whilst this is true, the question is what is actually taking place when two or metals or metalloids like germanium, are combined is that there are changes taking place to the atomic structure of the alloy. This requires us to take look at the underlying changes that are taking place to the metal during the alloying process.

Changes at the Atomic Level

Without turning this into a chemistry lesson, basically when different metals or metal-like elements are combined changes begin to take place to their atomic structure at varying degrees, with a combination of metals, as the atoms that are introduced to the main metal that is being alloyed (e.g. gold or silver) change or in context of jewellery making enhance certain features it contains, such as enhancing its hardness, and durability. The commonly found atomic structure in jewellery making metals is known as the Face-Centered Cubic (FCC), which is known for its ductility, making them easier to be shaped into the desired form, however, they are often too soft for durable long term use, hence their combination with another metal, like copper. Which plays the role of a substitution alloy, replacing some of the main metal elements, but retaining its structure, and hence its fundamental qualities. Next, we will look at certain popular precious metal alloys that are used in fine jewellery.

Gold Alloy

When understanding the use of alloys in fine jewellery there is no better to start than the top metal of choice: gold. Gold that is used in jewellery vary in terms of their alloy character, which in the industry are known by their distinct colours: yellow, rose and white gold; which are determined by distinct alloy combinations. The difference in the type of gold, in terms of their colour and hence alloy character, is something we have engaged in a dedicated page. Here we will look into the difference in gold alloys in terms of their purity or karatage. Notable here are the well known 18 karat, 14 karat, to the purer 24 karat. In addition, there are lesser-known gold variants: 10 karat and 22 karat types. 

• 10K: 41.7 per cent pure gold, with the rest being composed of various alloys. Used for affordable jewellery.

• 14K: 58.3 per cent pure gold with the rest being alloys. Arguably the most popular gold type, valued for its durability.

• 18K: 75 per cent pure gold, with alloys. Used in the making top quality fine jewellery.

• 22K: 91-92 per cent pure gold combined with nickel and/or copper. Rare in popular usage. Sometimes used for making speciality jewels.

• 24K: 100 per cent. Not used in the making of jewellery. Used in the making of gold bars, and coins, and is a measure of value.

Silver Alloy

In the world of fine jewellery making the most popular type of silver is sterling silver: an alloy that is composed of 92.5 per cent pure silver, with the remainder being various combinations of copper, nickel etc. Sterling silver jewellery are often marked with the 925 stamps. In recent times a new silver alloy in the form of Argentium silver has entered the market, containing a higher percentage of pure silver (93.5 – 96 per cent), with the noted addition of the metalloid germanium, which is understood to make it more durable and beautiful. With resistance to oxidisation being the notable feature, and a higher price. 

Platinum Alloy

Platinum alloying is an interesting subject since not much attention has been directed towards it. When purchasing platinum jewellery people don’t often consider what percentage is pure, in relation to the percentage of alloys. Platinum jewellery however does consist of some percentage of other metals, notably metals that fall into the same platinum group of metals: iridium, osmium, palladium, platinum, rhodium, and ruthenium. However, platinum is also known to be combined with varying levels of copper. Platinum purity is understood by the purity rating: 900 or 950, with the number corresponding to the percentage of pure platinum (90 or 95 per cent). Another interesting addition to the world platinum alloying is cobalt: a silvery metal that is known for its hardness and has been added in small amounts to strengthen alloys like platinum, for in contrast to other alloys like iridium, cobalt-platinum alloying are known to be less prone to porosity: manufacturing defects that occur to the metal in the course of its production. And is generally viewed as a better choice for manufactures.

Less Known Precious Metals

In the world of fine jewellery, with expanding expectations of customers, with diverse needs, the ability to meet their varied demands has given rise to new metal alternatives, either in terms of new types of metal alloys, or the addition of new metal types. Some of which have precious metal alternatives in their own right. Here we will look into top metals which have become popular, though still rarer in the world of fine jewellery.

Palladium

Palladium is similar in colour and character to platinum. As a member of the platinum family of metals, palladium exhibits a bright white appearance, which tends to fade in time, though it is patina finish is distinct from the yellowish shade developed by white gold. As a metal with a lower gravity (12.0) palladium is also a lighter choice when it comes to fine jewellery. Which may suit those who wish their rings and necklaces to feel light and less noticeable. The patina that develops over the years can be rectified by the simple process of polishing, or if you wish to be more careful, a quick trip to your local jewellery can restore its shine. It might interest you to note that palladium too is often layered with other metal alloys, like rhodium. Another metal in the platinum group. Rhodium plating, as we shall see is often applied to white metals helps to prolong the light, white finish and make them more durable. Palladium is also known for its malleability, a metal type that jewellers find easier to shape and fashion. Given its repertoire, a question one may ask is: Is palladium a viable substitute to platinum? That is not as an alloy, but as a new replacement to platinum: The answer is yes. Palladium jewellery has entered the market in recent years. And despite being rarer than its metal-cousin it tends to be cheaper, but finding quality palladium jewellery might prove to be a challenge.

Rhodium

A notable member in the platinum group of family, and renowned for its use in coating precious metals like white gold, rhodium is a new kid on the block when it comes to being a choice for fine jewellery. Though finding such items is almost impossible. As one of the rarest metals in the world, known for its white-silvery colour and high melting point, it may surprise you to note that there isn't a single rhodium mine in the world, and rhodium that is used in industry is basically a by-product of processing other metals. Rhodium whilst known for its plating qualities, when it comes to fine jewellery is a speciality item: as only a few jewellers produce jewellery from this metal type, so continues to be identified as a plating metal.

The Role of Jewellery Plating

Jewellery plating is a common industry practice when it comes to the making of fine jewellery. Since precious metals in their pure form or as alloys do not always exhibit qualities that match perfectly with the expectations of customers: in terms of comfort, durability, allergies and glow. Hence the market for jewellery plating, either in terms of enhancing the qualities of already expensive jewellery (fine) or in the cheaper market for jewellery gifts, where plated jewellery types are popular. Jewellery plating when it comes to fine jewellery, our main concern here revolves around a set of factors that are meant to enhance the innate qualities of the metal of the jewellery you going to choose. The effects of jewellery plating must always be beneficial, in terms of its effects on the metal alloy, and on your skin.

Minimising Allergies

In fine jewellery items like engagement rings which are meant to be worn for a long duration, often without removing them, thus the manner in which the metal reacts with the skin or ideally its absence is very important. Precious metals like gold are known to cause certain reactions with the skin, which can sometimes extend into full out allergies. One way to minimise such reactions is to opt for a metal type that is hypoallergenic and or to opt for metals that have been plated with less reactive metals that can minimise such effects. However, it is important to note that plating metals is the fix-all solution, and if you have a history of allergies, it is best to get a better grasp of the factors that are causing it. Again rhodium plating is a key addition, with rhodium-plated white gold being a popular choice.

Longevity

Longevity is a tricky word, for when it comes to fine jewellery the idea of endurance can mean the ring, for example, maintaining its sheen for longer and/or it could mean resistance to scratches. Or it could be mean greater hardness. The use of plating is meant to enhance one or more of these features of precious metals. Rhodium is again the main choice for jewellery plating as it improves resistance to scratches.

Replating Jewellery

Replating is a normal part of jewellery care. Notable when it comes to white gold replating, which can occur a number of times. This is a cost factor, that can cost dozens of dollars depending on the type of jewellery. So it is important to consider the kind of metal that you are choosing for your jewellery. Platinum as a principle tends to require less maintenance than gold for example, as it tends to chip less so. And when it comes to reactions, platinum is also a great choice. And unlike gold, it needs plating with rhodium or pallidum less.