Gold Carats Explained
The Timeless Appeal of Gold
Gold fascinates and enraptures us all and is one of the most prized metals in the world. It is famed for its rare nature, lustrous shine and ancient history and prized in jewellery-making, design, coin making, dental use, industry, electronics and high technology for its exceptional properties. It's even used in the manufacture of spacesuits! Gold is a chemical element, represented by the symbol 'Au' on the periodic table and with the atomic number of 79. It is soft, dense, shiny, ductile and malleable and in its purest form, has a bright yellow colour and high lustre that doesn't oxidise in water or air.
As well as gold's beauty and appearance, it is famed for being an international currency that holds its value when money systems fail. It has often been used in ancient societies as a currency for trade and bartering. Its current appeal continues today as a measure of value in a difficult economic system, where people are seeking certainty and safe investments, although some commentators do believe that gold as an investment has reached the top of a 'bubble'.
What is the Gold Carat System?
Most of us have a rough awareness of gold's carat (or karat in the USA) system, which grades this precious metal on a sliding scale of up to 24 carats, for 100% pure gold items. It's seen most commonly in everyday use when we're looking at jewellery and relating its price to the carats used to craft the piece. But what does it actually mean?
The carat system basically explains how much gold is present in proportion to other metals, meaning that the higher the carat of the gold is, the purer its composition is. Although it may automatically seem that 24 carat gold must be the most desirable type, for various applications, this pure gold is actually unsuitable due to its soft and malleable nature. A 24 carat piece of jewellery for example, would bend and scratch very quickly and become damaged. To make the gold harder and last longer, it will often be alloyed with other metals, depending on the ultimate use of the gold. For example, jewellery tends to be handled and used more intensively than gold bars or coins, so it is usually alloyed with copper, silver, platinum and nickel to help make it more durable. These often won't change the look and lustre of the gold at all but may be used expertly to create coloured golds, which are very popular in jewellery design and manufacture.
The carat system denotes the presence of alloys used in jewellery. Those familiar with gold will also know that hallmarks express gold in parts per thousand, such as 990 and 999 parts per thousand (with the remaining parts being copper or silver as an example). The hallmark of a piece of jewellery will be inscribed into it somewhere, usually on the inside of a ring or bracelet, where it isn't too visible.
24 Carat Gold
24 carat gold is pure and has absolutely nothing added to it. Its fineness is rated on the hallmark system as 1000, or occasionally 999, because it is incredibly difficult to get entirely pure gold without a single impurity in it (this also protects the manufacturer from any legal challenge too). Gold coins are usually 24 carat and rated as 999 parts to 1000. The Canadian Maples are a good example of this. Gold bars will generally be 24 carat gold too with a 999 hallmark system, bought as investments or alternatives to currency.
Other Gold Carats
The lower carats are measured on a sliding scale. 22 carat gold is measured as being 916.6 fine, 18 carats is 750 fine, 14 carats is 585 fine and 9 carats is referenced as being 375 fine. Other hallmark standards do exist, but these are the most common, telling the customer clearly how much gold exists in a certain piece. For example, 14 carats will be 585 parts gold, with the remaining 415 parts being other metals.
What Alloys are Used in Gold?
The alloys used depend very much on the eventual purpose of the gold. If it is being used for dental work or jewellery, the gold will need to be enduring and strong, so it's likely to be alloyed with copper or silver and occasionally with nickel or zinc. For dental use alloys, platinum and palladium are common thanks to their enduring natures. Other alloys will be used to create coloured golds and these are very popular in jewellery design and art.
How is Coloured Gold Made?
As well as using alloys to affect the hardness of gold in jewellery making, alloys can be used to create coloured golds. For example, rose gold can be created by adding silver and copper and nickel or palladium are added for white gold alloys. Copper alloys will give a redder colour, very popular for Russian and antique jewellery and even blue gold can be made with iron (purple with aluminium, although these are rarely seen, except for very specialist types of design). Green gold is found when 18 carat gold is mixed with silver.
What is the Most Popular Carat Used for Jewellery?
The most popular type of gold for jewellery making is 18 carat gold, which references a ratio of 75% gold and 25% other materials, generally silver or copper and sometimes a mix of both. It has all the lustre, appearance and beauty of pure gold, but with the hardness and durability of an alloy mix. Cheaper jewellery will often be made from 10 carat gold. Lower carats (anything less than 10) are arguably not gold, but more of an alloy mix. Other jewellery items will simply be gold plated, which means that gold has been applied to the item's surface and it is likely to wear off over time, revealing the alloy underneath. These are popular for more inexpensive, high fashion items that aren't designed to last. Watch out for items described as 'gold coloured', as these won't actually be made from gold metal, but rather other metals, compounds and even chemical dyes to create their appearances.
What about Gold Used in Industry?
14 carats are most commonly used in industry for industrial and manufacturing applications (such as circuit boards, pen nibs etc.), as well as bracelets and jewellery where durability is needed for heavier use. Many of us also have gold fillings or dental work, whether for cosmetic purposes or for medical dentistry. Gold is also used in medicine, especially some forms of natural and alternative medicine, as metallic gold is believed to have anti-inflammatory and healing powers (gold is often used by the pharmaceutical industry to treat arthritis) and is often found as an ingredient in luxury spa and beauty preparations.
What Carat Gold is Best for Jewellery?
It's tempting to assume that 24 carat gold is the most desirable type to go for but it won't make the resulting item any prettier, shinier or generally better. Most of the jewellery sold worldwide will be measured at 18k, 14k and 10k, depending on the budget available and the durability required from the piece. Remember that 24 carat gold is so soft, it can be moulded by hand and this means that most jewellery won't be made from this purest type of gold. It would become scratched and misshapen very quickly. 18 carat gold jewellery will last the test of time and can be beautifully coloured with specific alloys. Always check for the hallmark in high quality gold jewellery to establish the grade of gold that you are buying.