Metals Used In Jewellery Alloys
We all know precious metals can be expensive, but people want a variety of jewellery to suit the fashion or occasion, so jewellers have created a number of jewellery alloys – blending precious metals with cheaper metals – to keep fashion jewellery affordable. But just what is in those jewellery alloys?
Why a jeweller's alloy?
Jewellers' alloys are a mix of two or more metals, created for a number of reasons: to strengthen the metal ... to add a certain 'characteristic' such as tone or shine ... to keep prices down – but some metals cause allergies or skin reactions. We've all heard of cheap jewellery turning the skin green, haven't we? Most jewellers' alloys are created to strengthen softer precious metals, like gold, but some are used as the main manufacturing process and then plated with a precious metal to prevent allergic reactions and sensitivities.
What metals are in a jeweller's alloy?
Here is a list of common metals used in fashion and costume manufacture, together with their attributes, and possible 'side' effects.
Copper is the most commonly used metal in higher quality jewellers' alloys. It's hypo-allergenic and is said to have certain health benefits, such as easing the symptoms of rheumatism and arthritis. High quality fashion jewellery will have a pure copper 'core' plated in a precious metal, but copper is also blended with yellow gold to create rose gold, and mixed with other metals to form other alloys.
Cons: If the plating wears off, pure copper will tarnish and turn the skin green
Nickel was popular in jewellers' alloys for a long time owing to its malleability, workability, and low melting point for casting. It was alloyed with gold to give it strength, and, because of its low cost, used extensively in costume jewellery. However, nickel was discovered to be an irritant, causing rashes amongst those with a nickel sensitivity. Many countries have guidelines in place now for the use of nickel in jewellery, with only small amounts being permitted. If you have a nickel allergy, always look for the nickel-free or hypo-allergenic label.
Pros: Cheap, workable.
Aluminium is relatively new to the world of jewellery making. It's not as thin and tearable as aluminium wrap would have you believe, but still as shiny, making it attractive for jewellery use. When given certain treatments, aluminium can be 'dyed' to produce a range of bright colours, making it a rising star in the world of fashion jewellery.
Pros: Resistant to corrosion, easy to colour
Cons: Difficult to solder, so use is mainly restricted to casting the whole piece.
Tin is an affordable silvery metal frequently used in jewellery alloys, particularly in the production of bronze and pewter.
Pros: Resists corrosion
Zinc is a silvery metal used in alloys to reduce the melting point. It's commonly used in white gold.
Manganese is generally used as a hardener to make precious metals more durable.
Chromium Chromium is generally used in stainless steel and surgical steel. It lends a bright silver colour and is easy to sterilise.
Pros: Corrosion and scratch resistant. Non-irritant.
Lead used to be used in almost every area of life - plumbing, paint, roofing, toys and jewellery - but then we realised that lead is actually a very dangerous substance. High levels of exposure to lead can injure the brain and nervous system, so most developed countries have banned the use of lead in jewellery manufacture. However, as lead is also naturally present in and alongside many other metals and everyday substances, it is very difficult to eradicate totally so trace amounts are permitted.
Pros: Soft, cheap and abundant.
Cons: Harmful to health
Common Jewellers' Alloys
Brass is an alloy of copper and zinc, resulting in an easy-to-cast metal with a rich golden colour. It's a very durable alloy for jewellery use.
Pros: Cheap, corrosion resistant
Cons: Can turn green if a lot of copper is used in the mix.
Bronze is a pretty metal alloy popular in vintage-styled jewellery. It's a mix of copper, tin and zinc.
Cons: May contain traces of allergenic/harmful metals such as nickel and lead. Tarnishes.
Pewter is an alloy of tin and copper, occasionally (historically) with lead included. Pewter is fairly soft and can be finished in either a shiny silver or darker "antiqued" silver. Pewter is the fourth most commonly used metal in jewellery manufacture. Lead was once added to pewter as a hardener, but this practice has been banned in many countries because of lead's known adverse health affects.
Pros: Easy to cast and mould
Cons: Soft enough to dent and scratch.
Stainless Steel / Surgical Steel
Steel is an alloy of several metals, mainly iron, chromium, nickel, titanium, carbon and copper amongst other trace elements. It's cheap, corrosion resistant and durable.
Pros: Strong. Stain and tarnish resistant. Cost effective.
Cons: Does require regular cleaning to maintain its look.