Metal Definitions and Descriptions
First, a few definitions:
Hypoallergenic means “below normal” or “slightly” allergenic. The term was coined by the cosmetics industry in the 1950’s, and became a popular marketing term for jewelry soon afterwards.
Many people are allergic to nickel, so “nickel free” and “hypoallergenic” are sometimes considered synonymous. Be aware that hypoallergenic does not mean nickel-free, nor does it have a legal or medical definition for use in jewelry. You’re better off using specific materials rather than the vague term “hypoallergenic.”
Many people believe that stainless steel is nickel free, but most stainless steel alloys (even surgical stainless steel) contain 8-12% nickel. Roughly 6-12% of the population is allergic to nickel, so although it’s legally acceptable to put a “hypoallergenic” label on all stainless steel, it doesn’t seem quite fair to those who are looking for nickel-free jewelry.
Elements and Alloys:
Alloys (such as stainless steel, sterling silver and 14kt gold) are mixtures of elements (such as iron, gold, copper and zinc). People create alloys to change the color, melting temperature, and/or strength of lone elements. For example, solid gold is too soft for ear wires — to make it stronger, it is alloyed (mixed) with other elements such as silver and to make 14kt or other alloys of gold. Iron is alloyed (mixed) with other elements primarily to make it stronger and resistant to rust.
Nickel Free or EU Nickel Directive?
Since there isn’t a formal US definition of nickel free, and alloys vary, a good way to find items that are very low nickel, is to search for items that say they meet the EU Nickel Directive. Another method is to avoid alloys entirely, and focus on elemental metals such as niobium and titanium. For more information about the term “nickel free”, see our Nickel-Free Metals Information page.
Good Metals to try:
Because different people are allergic to different metals, there is no “one size fits all” solution. However, some metals are known to cause fewer problems than others.
Niobium is an excellent choice for people with metal allergies. It is highly resistant to corrosion and other reactions, and is used in medical implants. Niobium is not plated or painted, so the color will not flake or chip. It is anodized, meaning it is colored by dipping it into an electrically charged “bath.” Because it is an inert element, with no nickel, lead, or other additives, most people with metal allergies can safely wear niobium. It doesn’t match basic silver and gold colors — but it is available in rich black, copper, blue, bronze, green, pink, purple, teal and yellow.
Titanium is a very strong metal, frequently used in medical implants, and is another excellent choice for people with nickel allergies.
There are over 100 alloys of stainless steel, and each is denoted by a unique SAE steel grade number, which may include one or more letters. Stainless steel alloys include steel (iron with carbon), chromium for scratch resistance and corrosion resistance, nickel to reduce brittleness and improve strength at both high and low temperatures, and other trace elements. For stainless steel alloys used in jewelry, these trace elements are approximately 0.75% silicon, 0.045% phosphorous, 0.03% sulfur, 2% manganese, and 0.1% nitrogen.
304 stainless steel is the most popular grade of stainless steel. It is 18-20% chromium, 8-10.5% nickel, 0.08% carbon, plus iron and the trace elements listed above. It is commonly used in the food industry (sinks, coffee urns, dairy storage and hauling, beer/brewing, citrus and fruit juice handling, etc). The same corrosion and stain resistance that make it great for food handling, also make it popular for jewelry.
430 stainless steel contains less than 0.75% nickel, and some forms of 430 stainless steel meet the EU nickel directive (less than .05% nickel ion migration). 430 stainless steel has good corrosion resistance compared to non-stainless steel, but not as good as the 304 and 316 alloys.
Surgical Stainless Steel
Adding the word “surgical” to a stainless steel alloy’s name does not make it is better grade of steel. The SAE grade number (304, 430, 316L, etc.) defines the alloy and its properties, so the word “surgical” simply tells us “non-SAE-tech people” that 316 and 316L stainless steel alloys have properties suitable for temporary medical implants, or for making durable surgical instruments.
316 and 316L surgical stainless steel contain 2-3% molybdenum for even greater resistance to harsh corrosives (both industrial, and in the body). 316L is a low carbon version of 316, with extra corrosion resistance, and is frequently used for stainless steel watches and marine applications. Like most other stainless steel, it contains 8-10.5% nickel, making it unsuitable for people with nickel allergies.
Sterling Silver and Fine Silver
Sterling silver is an alloy containing at least 92.5% silver. The most popular sterling silver alloy is 92.5% silver and 7.5% copper. To prevent tarnish while on display in department stores and high-end jewelry stores, some sterling is plated with rhodium. Most people can safely wear good quality sterling silver, but a few are allergic to silver or copper. Sterling silver from reputable vendors is nickel free, but be aware that some jewelry marked sterling or 925 — especially if the price seems too good to be true — may contain little or no silver at all, or be alloyed with random metals.
Argentium™ sterling silver replaces some of the copper with 1.2% germanium (the remainder is 6.3% copper and 92.5% silver). Argentium sterling silver is tarnish resistant, laser weldable, and has other unique properties.
Silver fill (also called silver overlay) is made by using heat and pressure to apply a layer of sterling (.925) silver to a base of less costly metal, usually brass. The minimum layer of silver must equal at least 1/20 of the total weight of the item. Silver fill is 100’s of times thicker than silver plating, so it lasts many years longer before wearing through the layer of silver. If you can wear sterling silver, you can most likely wear silver-fill items for quite a few years before you wear through the top layer to any irritating basemetal layers beneath it.
Vermeil, pronounced “vehr-MAY” [French], is gold plated sterling silver. If you can wear sterling silver, it’s very likely that you can wear vermeil.
Karen hill tribe
Fine silver, sometimes stamped “.999″, is 99.9% pure silver, which means it is softer and more malleable than sterling. It is commonly used for bezels, handmade ball-end head pins, and components made by the Karen Hill tribes.
Just like sterling silver, fine silver can be misrepresented. If you’ve experienced allergies to cheap items marked sterling, 925 or 999, you may want to try again from a reliable, knowledgeable vendor before you rule out silver entirely.
Pure gold is 24kt, meaning 24 out of 24 parts are gold. 24kt is too soft to be functional, so it is alloyed with other metals for durability, cost and color. 14kt is 14 parts gold out of 24, and the remaining 10 parts are other metals. Depending on the color of gold (which can be yellow, rose, green or white), the other parts may be copper, silver, nickel, zinc, tin, palladium and/or manganese. People with nickel allergies should be aware that, until recently, most white gold contained nickel. Today, palladium is used to make a white gold alloy that is less likely to react to the wearer’s skin.
14kt GF is made by using heat and pressure to apply a layer of karat gold to a base of less costly metal. This produces a surface with karat gold. The minimum layer of karat gold must equal at least 1/20 of the total weight of the item. Gold fill is 50 to 100,000 times thicker than regular gold plating, so it lasts many years longer before wearing through the layer of gold. If you can wear 14kt gold, you can most likely wear gold-fill items for quite a few years before you wear through the top layer to the brass or other basemetal beneath it.
Copper and Brass
copper heart blank
Copper is a lovely reddish metal. It is easy to work with, but oxidizes quickly, and where it comes into contact with skin, can turn skin green. The “green skin” factor makes it unpopular for ear wires or earring posts. You can lacquer (or otherwise coat) it, but high contact points — such as going through an ear — wear off quickly.
Alternatively, many people believe that copper can prevent arthritis, so solid copper bracelets are popular. For this effect, it needs to touch (and react with) your skin, so skip any protective layers.
Brass is an alloy of copper and zinc. Depending on the desired properties, the percents of copper and zinc can vary greatly. Because brass is usually 50-90% copper, it has roughly the same “green skin” properties as copper. Cheap brass earrings may have irritating impurities in their alloy, causing an allergic reaction to people who aren’t allergic to either copper or zinc.
Brass is a popular material for plated ear wires, because it is inexpensive, easy to plate or electrocoat, and is relatively allergy-free.
(From Rings and Things Blog post 12/14)