Gold, with its timeless beauty and symbol of wealth, has fascinated humanity for centuries. Its use in jewellery, investment bullion, coins and various industrial applications stems from its exceptional properties, including its resistance to corrosion. But a common question remains: Can gold rust?
Understanding Gold’s Properties
Gold is an extremely stable metal which is resistant to oxidation and corrosion. Unlike base metals such as iron, gold does not react with oxygen in the air, which is why gold does not rust. This resistance to tarnishing and corrosion makes gold ideal for many applications and is a big reason to why it has been used for jewellery for centuries.
What is Pure Gold?
Pure gold which is referred to 24-carat, is composed entirely of gold atoms and nothing else. It is known for its distinct, rich yellow colour and unmatched malleability – allowing it to be shaped into intricate designs without shattering or snapping. However, because of its relative softness, pure gold is often alloyed with other metals to enhance its strength and durability for everyday use.
Factors Influencing Gold’s Corrosion
While pure gold does not rust or tarnish, gold alloys can experience some of these undesirable affects in specific environments. The addition of other base metals into the alloy can create pathways for corrosion.
Exposure to Corrosive Substances
Gold alloys can be affected by corrosive substances like chlorine, acids, and sulphur compounds. When jewellery made from lower carat gold is exposed to chlorine, the non-gold metals in the alloy may react to cause discoloration.
Timeless Investments
Pure Gold Coins
The Gold Britannia and the Gold Sovereign are the most popular bullion coin for British investors
The Britannia is struck in 999.9 fine Gold, making it pure Gold. Sovereigns are less fine, at 91.67% pure
Environmental factors can also influence the corrosion of gold alloys. High humidity and frequent exposure to saltwater can accelerate tarnishing in gold jewellery. In coastal areas, the presence of salt in the air can increase the risk of corrosion over time of the metals mixed with the gold.
Chemical Reactions within Alloys
Different metals in gold alloys can react chemically over time. For example, copper can react with oxygen to form copper oxide, which appears as a dark layer on the surface. Perspiration can also lead to a change in humidity on the surface of the gold which can increase the risk of copper reacting.
Whilst the oxidation does not impact the gold itself, it tends to affect the appearance of the alloy. Collectors of Mexican gold coins may have seen a similar effect on the surfaces of their coins as the copper reacts to give a red spotting appearance.
Temperature Fluctuations
Extreme temperature fluctuations that the jewellery is exposed to can also affect gold alloys. This is because the action of heating and cooling cycles will have different effects on each different metal within the gold alloy, leading to the expansion and contraction at different rates. This increases the risk of stress cracks where corrosion may later develop.
Length of Exposure
How long the gold alloy is exposed to corrosive elements is a big factor too. Prolonged exposure to harsh conditions can lead to more severe tarnishing and corrosion, even in higher gold purity alloys.
Gold Investments
Most Popular Gold Coins
Gold Sovereign coins are the most popular investments with British Gold buyers. their price point, low-premium and history all contribute to a vhighly sough investment. Check our prices and availability today