Precious Metal Information
Gold : White Gold : Platinum : Silver
Gold
Gold was first used over 5,000 years ago in Mesopotamia, giving it the longest history of any precious metal. It has never lost its unique appeal. Soft enough to be worked into all manner of forms, gold is so malleable that just 20 grams (0.6oz) can be stretched into a wire more than a kilometer long (over half a mile), or beaten into a sheet of over 20 square metres (210 square feet).
Gold’s rarity and warm colour gave it great value for early civilizations, and it has long formed the foundation of worldwide monetary systems. Up until World War I, the Gold Standard was the basis for world currencies, and remains important to our economy even today.
For jewellers, gold's softness and natural beauty have always been appealing, as well as the fact that it doesn't corrode or tarnish. Pure gold is so soft, in fact, that it’s rarely used in jewellery. Instead, it’s mixed with another metal, usually copper or silver, to make a stronger gold alloy (mixture of metals).
The quantity of gold in a given alloy is expressed in carats (ct). Pure gold is 24ct, and 75% gold is 18ct. At lower carat values, the metal can become more durable, but less yellow. So lower carat gold is sometimes plated in high-carat gold to enhance the colour. There’s nothing wrong with this, but keep in mind that gold plating will wear off with time, and your jewellery may need to be re-plated.
When buying gold jewellery, look for the “hallmark” (the manufacturer's registered trademark), a standard mark telling you the carat value, and a guarantee mark, which shows that a third party has tested and warranted the quality.
White Gold
White gold was developed to give a different look to jewellery. The white colour is an excellent setting for very white diamonds, and when used side by side with yellow gold, it creates a striking effect.
White gold has the same properties as yellow, but has been mixed with different metals, such as nickel, zinc or even platinum, to create the white colour. However, white gold should not be confused with platinum, which is much rarer than gold – and so more valuable.
The carat system used in white gold is the same as that used in yellow gold. 18ct gold contains 75% gold whatever the colour; only the remaining 25% of the alloy is different. White gold is sometimes plated with an even whiter metal, such as rhodium (a very rare member of the platinum family), to enhance its appearance.
Platinum
Silvery-white platinum is the most precious metal commonly found in jewellery. A relative newcomer, platinum has only become popular in the past 200 years or so. It is quite difficult to work, and is seldom found in fine jewellery before 1900. Platinum is rare and heavy like gold, but is more durable, so it’s sold in purer form. For added strength, it’s sometimes mixed with a little iridium and ruthenium, which are similar to platinum but much rarer.
Platinum is not sold according to carats. It used to be stamped ‘PT’ or ‘plat’ in the UK, to indicate that it was platinum. But since January 1 1975, all platinum items in the UK weighing over 0.7g must be hallmarked, just like gold and silver.
Because of its purity, platinum is excellent for people who are allergic to other metals. It’s also popular for its light colour. Like white gold, it doesn’t reflect any yellow colour into white diamonds, so it won’t detract from their brightness.
Platinum has enjoyed an enormous resurgence in popularity in recent years. Its very understated, old-fashioned look has come back into style, leading more and more jewellery designers to work with platinum.
At Lanes the platinum we sell is 95% pure; one of the purest forms you can buy on the high street.
Take your platinum piece to us for polishing if visible scratches appear. All precious metals can scratch, and platinum is no exception. However, the scratch on platinum is merely a displacement of the metal and none of its volume is lost.
Be aware that, over time, platinum develops a natural patina that many people prefer over the "just polished" look
Interesting facts about Platinum
All the platinum ever mined from the beginning of time would fit into a typical living room.
The coronation crown of the Queen Mother was made from platinum.
The Kohinoor (Mountain of Light) diamond, part of the crown jewels is set in platinum.
Around two tonnes of ore has to be mined to obtain enough platinum to make a ring.
Platinum's melting point is almost double that of gold.
Platinum is used in the hard discs of most PC's to improve capacity and durability.
Platinum is resistant to attack from most chemicals.
The only material suitable for the electrode in heart pacemakers is platinum.
1 gram of platinum can be made into wire 2 kilometres long.
One third of the platinum mined in the world in 2005 was made into jewellery.
There is no platinum in a platinum record; it's only plastic dipped in silver.
It takes 8 weeks to refine pure platinum from the ore extracted from the earth.
Silver
Silver is much more plentiful than gold. But because it tends to tarnish, it’s less popular in some forms of jewellery. Like pure gold, pure silver is too soft to use, and must be combined with other metals. And, as with gold and platinum, silver items over a certain weight must carry a hallmark.