In this article we will try to answer a common question that comes up - what is the difference between platinum and gold?
Let's look at gold first.
The exact date that gold was discovered is unknown, however it is widely accepted that its discovery was somewhere around 2,500 BC.
Since then, gold has been used for jewellery, used in medicine and healing, been traded internationally, and been the precursor to many wars.
In its pure for gold is a bright yellow colour and actually quite soft and malleable, and refined with other alloys to increase its hardness and alter its colour.
18ct for example is often stamped 18ct, 18k or 750 or.750, where in this case 750 represents a percentage of gold versus other alloys, and 750 simply means that there is 750 parts of gold per thousand or 75% gold.
9ct can be stamped .375 meaning 37.5% gold, 14ct can be stamped 585 (58.5% gold) 15ct can be stamped 625 (62.5%) 22ct can be stamped (91.6%). However 24ct gold in jewellery is often stamped 999 meaning 99.9% pure because it is assumed that there will be 0.01% impurity in the gold.
The three most common colours for gold is yellow, white and rose or pink gold. White and rose gold is caused by adding alloys that will change the colour of the gold, for example copper is added to make rose gold where the more copper, the more intense the colour.
White gold has had its alloys changed over the years - namely due to the cost of the other alloys, however white gold is produced by adding either manganese, silver, palladium or nickel or a combination of two of these materials.
Years ago palladium was the metal of choice due to it being able to make the white gold retain its "whiteness" but the cost of palladium has increased dramatically (at one stage overtaking platinum in price!) compared to the other metals meaning the other metals are now used more and it is quite common and accepted to rhodium plate white gold after a piece of jewellery is made to give it a high mirror finish look in a pure white.
Other colours that can be produced is green gold by adding cadmium, however cadmium releases toxic fumes when being melted and was mostly only used during the Art Nouveau period of the late 1800's and used as a "highlighting" gold such as gold "leaves" in a brooch.
Blue gold, black gold (not to be confused with black rhodium) and purple gold can also be made however it is white, yellow and rose that have remained the clear favourites over the last 100 years.
Platinum is a very different metal to gold in so many ways.
Firstly even though it was discovered in 1557, it wasn't really until the early 1900's and slightly later the Art Deco jewellers of the 1920's that platinum was consistently used in making jewellery. Prior to that from around 1780 onwards, the platinum was hammered and forged onto jewellery rather than being made from it. The reason is that platinum has a much higher melting point at 1755 Celsius which meant that until the invention of the oxyhydrogen torch in the mid-1800Ã¢â‚¬â„¢s that could now melt platinum, this was the only way that it could be used in jewellery.
When platinum is used in jewellery it is kept very pure and ranges from being stamped 900 (meaning 900 parts of platinum per thousand or 90% platinum) to 935 and 950. As a side note, 935 is used instead of the middle range between 900 and 950 of 925 due to the fact sterling silver is both 925 and the same colour as platinum and confusing the two would be far too easy.
Platinum is also very durable when compared to gold and due to the high purity used in jewellery, platinum retains its "whiteness" and does not need to be rhodium plated.
It is also able to be drawn into a very fine wire while still retaining its strength and is wonderful in such pieces as brooches with very fine platinum wire even set with diamonds such as in the Art Deco era, or can be seen in platinum diamond engagement rings for example.
It is also denser than gold and a white gold wedding band with the same dimensions and size as a platinum band will be the lightest of the two.
Years ago platinum was considered the choice of metal to use as it is rarer than gold, more difficult and expensive to extract from the ground compared to gold making platinum somewhat "exotic" and used for the higher end pieces, however while all of this remains the same today, the price of gold has risen dramatically and is very close to be on par with gold.
Many Art Deco rings of the 1920's will often be made with a gold band (either white or yellow) and the top of the ring made in platinum, and today it is more common that if the band is yellow gold then the top will be in white gold.
So which is best to use for a diamond engagement ring? There will be a few factors here. Whereas before price was really the governing factor - a loose rule of thumb was that whatever it cost to make in white gold, double that price if it is in platinum and this rule does not apply now (though the labour needed by working in platinum is greater, so expect to pay more for labour costs), it really comes down to personal choice. Platinum will always have that more "exotic" and "selective" feel about it and being purer will not require the maintenance of white gold, however there will always be more rings out there in white gold than platinum so there will be a much greater choice of ring, there really is no right or wrong as both metals are wonderful and both really are set to stay for another 100 years for making jewellery.