Platinum

What is platinum?

Platinum is a dense, rare, dark-silver coloured, and very hard-wearing metal that has a variety of uses in industry, science, and jewellery.

Platinum is very dense and heavy, almost exactly twice as dense as silver, and this often helps to identify platinum nuggets found in nature. At first glance, platinum nuggets are unremarkable looking, with a dull surface, however their weight will give them away. It’s rare to find platinum in large nuggets and most of the platinum mined today comes from ore that is combined with other metals, such as nickel and rhodium. Platinum is often a byproduct of nickel mining.

Platinum is a noble metal, which means it is highly unreactive. This means that it does not tarnish like silver. The tarnish on silver is a result of oxidisation, as silver atoms react with oxygen atoms. However, platinum does not react and undergo the same process, no tarnish is created.

Platinum jewellery

Today, platinum is a very well known metal to jewellery lovers. Its natural properties of durability and strength, whilst also being somewhat ductile and workable, and its ability to be polished to a high shine, make it ideal for housing fine gemstones.

Platinum has been used in jewellery for centuries, however its rarity means it’s not nearly as common as gold in the historical jewellery record. In recent history, platinum has been significantly more expensive than gold, so has been inaccessible for some. However, this has changed in the last couple of years and platinum is more or less the same price as gold, per gram, now.

In the 1920s, platinum was often used in conjunction with gold to provide a white metal backdrop to set diamonds into. As diamonds are traditionally more desirable if they appear whiter, having them set into a white metal, as opposed to yellow gold, helps them to appear colourless and thus more valuable.

Platinum is more suitable for some types of jewellery than others. Its weight, for instance, means it is less suitable for earrings, as heavy earrings can pull on the ear and cause discomfort and deformation. There is no need for the extra strength and durability that platinum offers either, as earrings do not often come into contact with surfaces that are abrasive in the same way that rings do.

Again, because of its, weight platinum is less well suited to bracelets and necklaces, as these pieces tend to be larger and, therefore, already heavier.

Platinum is best suited for rings and it is a popular choice for engagement and wedding rings. Its strength and density mean that claws made from platinum will wear better than those made from white gold and need to be replaced less often. It is also advised that if you have an engagement ring made from platinum, you should have a wedding made from platinum as well, as the two will wear evenly against each other. A white gold ring, on the other hand, will visibly wear down if continuously worn next to a platinum engagement ring.

Working with platinum

Although the properties of platinum make it an excellent material to have jewellery made out of, these same properties can make it tricky to make jewellery out of.

For one thing, the melting point of platinum is over 3000 and, when soldering platinum, it glows so brightly that eye protection must be worn to protect the craftsman.

As platinum is very strong, it needs to be annealed (heated evenly and then left to cool slowly) to make it more malleable as it hardens significantly when worked. This adds time to any job, therefore increasing cost.

Platinum’s density also makes it ‘sticky’ and in order to achieve an even finish and high polish, extra time needs to be taken and finer grades of emery paper applied than would be necessary for gold or silver.

Where does platinum come from?

Platinum mining

80% of the world’s platinum production comes from mines in South Africa, with most of the rest coming from Canada and Russia. Although there is

The process of mining and then refining platinum is expensive and complicated, and it is this, along with the metal’s rarity, that keeps prices high.

Platinum as a sustainable material

Unlike gold, there are no certified sources of platinum from mines which meet high environmental or workers’ rights standards. As the mining, and especially the refining, of platinum, is very complicated and expensive, there is almost no small scale platinum mining and there is unlikely to be any mined platinum in the future that will be Fairtrade or Fairmined certified.

Whilst some metal suppliers do offer ‘recycled’ platinum for jewellery, this offers no environmental benefit, as it does not decrease demand for the metal.

As with all precious metals, if the price of the metal remains high enough for mining to be profitable, then mining will continue. Additionally, platinum has always been recycled, so this is no major change for the industry.

How much does platinum cost?

For much of recent history, platinum has been more expensive than gold. Often, it has been more than twice as much, though that has changed in the last couple of years, and the metals are currently very similar in price per gram. However, items of platinum jewellery will often still be slightly more expensive than an identical item in white gold. This is because platinum jewellery is made out of alloys that are 95% pure platinum, as opposed to gold alloys, which are typically only 75% pure gold. Platinum’s density also contributes to this higher price.

As well as use in jewellery platinum is used for a number of other applications as well as held as an investment and its use across other industries, specifically automotive, that has contributed to its recent drop in price.

Platinum alloys

The most popular platinum alloy that is used in the jewellery industry in the UK is ‘950’, which is 95% pure platinum. This is a very high percentage of metal when compared to the two most popular alloys for gold which are just 37.5% (9ct gold) and 75% (18ct gold) pure gold.

There are a variety of metals which are added to platinum and constitute the other 5% of the alloy. Different metals have different properties, which make the alloy more suitable for creating jewellery. Rhodium, iridium, cobalt, ruthenium, and palladium are the most commonly used for slightly different reasons.

Most machined wedding rings sold in Europe are made from ruthenium, platinum alloy, as this has an excellent white colour, good ductility and is malleable enough to make it suitable for manufacturing.

In rare cases, the use of the wrong alloy can result in items of jewellery failing, sometimes resulting in gemstones becoming lost or damaged.

“Using the appropriate alloy is absolutely vital. The disputes that arise from these cases can be very difficult to resolve and the end customer is usually very emotionally attached to his or her ring. Manufacturers can save themselves and their customers a lot of heartache by using the appropriate alloy.” - Dippal Manchanda, Birmingham Assay office

X-ray fluorescence analysis can be used to determine the exact composition of an article of platinum jewellery.

Platinum hallmark

Any item of jewellery sold in the UK that is described as being platinum must be hallmarked, and this is carried out at any one of four assay offices in the UK. A hallmark contains 4 or 5 stamps, which signify that the item has been tested for purity, on what date it was hallmarked, which assay office carried this out, the fineness of the metal, and the traditional fineness symbol.

There is also an optional sponsors’ mark to identify the maker of the piece. All platinum articles which weight above 0.5g must be hallmarked in accordance with the hallmarking act of 1973.