The four Precious Metals most often used in jewellery are Gold, Platinum, Palladium and Silver.
All come in different qualities, or carats, and sometimes in a range of colours, depending on the alloys used in making the final article, or on over-plating.
Each manufacturer and maker has their own, closely guarded, preferred alloy composition. There is constant development and experimentation to improve their various characteristics as these influence colour, durability, hardness, lustre and workability for both casting and forming.
All precious metals sold in the UK must be Hallmarked as an independent guarantee of quality and purity.
Gold is a highly sought-after precious metal which, for thousands of years, has been used as currency, a visible symbol of wealth and self adornment.
Its chemical symbol is Au from the Latin aurum, meaning shining dawn.
Gold is found in igneous rocks and quartz veins, or in the form of nuggets and grains in river beds. The main mining areas are Africa, the USA, the former USSR, Canada, Australia and South America.
Gold is dense, soft, shiny and the most malleable and ductile of the known metals. Pure gold is 24ct. The purity of gold jewellery ranges from 9 carat, at the lower end through to 14ct, 18ct & 22ct. Pure gold is too soft to be practical for jewellery. In the UK, all Gold products must be hallmarked to indicate the purity of the alloy used in the making of the piece.
Rose Gold contains a higher percentage of copper in its alloy mix, which gives the characteristic pink hue to the metal. The depth of colour will depend on the exact proportions of copper and other alloys in the mix, so one 9ct Rose Gold ring will not necessarily be identical to another if they are made in different workshops.
White gold is achieved by mixing yellow gold with white alloys, such as cobalt, zinc, palladium or even platinum, then by rhodium plating the finished article. The external white colour which you see is therefore usually rhodium and not gold. This is why there is no visible difference in the appearance of 9ct and 18ct white gold, unlike the same carats of yellow gold. In time, the rhodium inevitably wears, especially on rings, and the item will require regular replating.
In the past, white gold was the only economical alternative to Platinum, and a more durable alternative to Silver, when a white metal was required in jewellery. However, now that Palladium has its own hallmark there is another alternative although 9ct white gold certainly has its advantages.
Platinum is a naturally white metal so will never fade or change colour (unlike white gold). It is the best metal in which to set diamonds, but it is also the most expensive. A Platinum setting enhances the brilliance of diamonds and other gemstones. Along with Palladium, it is generally used for the mount of diamonds in yellow gold rings, so that their colour is not affected by reflected yellow tints.
In the UK, platinum jewellery is typically hallmarked at 95pc purity, making it purer even than 22ct gold. The remaining 5pc is made up of alloys which improve its workability.
Platinum is hypoallergenic, so is a good choice for anyone with metal sensitivities or allergies.
Palladium has been used in jewellery for many years, most commonly as a mount for diamonds in a yellow gold ring, or as an alloy in Platinum jewellery.
It is now used increasingly in its own right as a jewellery metal since receiving its own hallmark in 2009. It has become particularly popular as an alternative to Platinum and white gold for reasons of both cost (similar to the cost of 14ct gold) and colour - as it is another naturally white metal.
Platinum and Palladium are very close to one another on the chemical periodic table and share many physical characteristics. Palladium jewellery is as pure as platinum, and is nearly as hard, but Palladium is half the density of Platinum so does feel much lighter on the hand, and wears less well over the years.
Palladium is particularly popular for men's wedding bands where a white metal is required, but it is used increasingly in engagement rings for both genders. It's lower cost allows couples starting out to put more of their scarce resources into their diamond of choice.