Have you ever noticed your gold jewellery losing its shine or even changing colour? It can be puzzling, especially since gold is known for its resistance to tarnish and corrosion. So, why does gold jewellery discolour over time? The reasons lie in chemical reactions, environmental factors, and even daily habits. Let's explore the causes and solutions to keep your gold jewellery looking radiant.
Why Does Gold Jewellery Discolour?
Gold itself is a noble metal that doesn’t tarnish or corrode. However, most gold jewellery isn’t made from pure gold but is alloyed with other metals like copper, silver, nickel, or zinc to enhance its durability and strength. These additional metals are the primary reason for discolouration, as they can react with environmental factors.
1. Sweat and Body Oils
Our sweat contains various chemicals, including chlorine and sulphur compounds. When these come into contact with the metals alloyed in gold jewellery, they can cause chemical reactions, leading to discolouration. For instance:
- Chlorine reacts with silver in the alloy, forming black silver chloride.
- Sulphur reacts with copper, resulting in black copper sulphide.
- Mercury (found in trace amounts in some people’s sweat) reacts with gold, forming a white amalgam called gold amalgam.
Solution:
- Remove jewellery before exercising or in hot, humid conditions.
- Clean your jewellery regularly to remove body oils and sweat residues.
Learn more on how to maintain your gold jewellery’s shine in our Gold Jewellery Care Tips.
2. Cosmetics and Skincare Products
Many cosmetics, including lotions, perfumes, and makeup, contain chemicals that can react with gold alloys. Common culprits include:
- Mercury in some skin-lightening products, which can cause gold to turn white.
- Lead in certain cosmetics and hair dyes, leading to black discolouration.
- Micro-particles in exfoliants and powders can scratch or dull the jewellery’s surface.
Solution:
- Apply cosmetics and let them dry before wearing jewellery.
- Avoid direct contact between jewellery and beauty products.
3. Environmental Factors
Gold jewellery can also discolour due to environmental exposure:
- Air pollution: Sulphur compounds in polluted air can react with silver and copper in gold alloys, leading to black tarnish.
- Moisture and Humidity: High humidity accelerates the chemical reactions that cause tarnishing.
- Chemicals in Water: Chlorine in swimming pools, salt in seawater, and even chemicals in tap water can react with gold alloys, causing discolouration.
Solution:
- Store jewellery in airtight containers to minimise exposure to moisture and pollutants.
- Avoid wearing gold jewellery while swimming or bathing.
4. Friction and Contact with Other Metals
Gold is a relatively soft metal, and when it comes into contact with harder materials or other metals, it can lead to discolouration due to friction and abrasion. This includes:
- Contact with keys, coins, or other jewellery, causing scratches and dullness.
- Rubbing against metal watch bands or other accessories, transferring metal residues.
Solution:
- Store each piece separately to avoid scratching.
- Remove jewellery before engaging in activities that involve heavy contact with other metals.
5. Age and Wear
Over time, the surface of gold jewellery can wear down, revealing the underlying metals in the alloy. This gradual wearing can cause:
- Dulling or fading of the gold’s original colour.
- Exposure of copper or silver alloy components, which are more prone to tarnishing.
Solution:
- Regular polishing by a professional jeweller to restore the gold's shine.
- Consider re-plating for gold-plated jewellery.
How to Prevent Gold Jewellery from Discolouring
- Proper Storage: Store in airtight, anti-tarnish bags or boxes to prevent exposure to moisture and pollutants.
- Regular Cleaning: Clean with a soft cloth or mild soap and water. Avoid harsh chemicals.
- Protective Coating: Consider applying a clear protective layer to prevent direct exposure to chemicals.
- Professional Maintenance: Have your jewellery professionally cleaned and polished annually.
Keep Your Gold Jewellery Shining Bright
Gold jewellery is an investment in beauty and elegance, but it requires care to maintain its brilliance. By understanding the causes of discolouration and adopting preventative measures, you can keep your gold pieces looking as good as new. Whether it’s avoiding certain cosmetics, storing them properly, or getting them professionally polished, a little care goes a long way.
Can pure gold discolour?
No, pure gold (24K) does not tarnish or discolour. However, most gold jewellery is alloyed with other metals, which can react and cause discolouration.
Does white gold discolour as well?
Yes, white gold is typically rhodium-plated. Over time, the plating wears off, revealing the yellowish tint of the gold alloy underneath. Re-plating can restore its original look.
How often should I clean my gold jewellery?
Clean your gold jewellery at least once a month if worn regularly. For pieces worn occasionally, cleaning every few months is sufficient.
Why does my gold jewellery turn my skin green?
This is usually due to copper in the gold alloy reacting with sweat or skin oils, leaving a green residue on the skin.
Can I reverse the discolouration of gold jewellery?
Yes, professional polishing and cleaning can restore the original shine and colour of gold jewellery.
