Metal Mania--Precious Metals
When I’m selling my jewelry at an art fair, I often tell my customers that I use quality metals such as sterling and fine silvers, gold-filled metals, brass, stainless steel, and copper. Most importantly, I assure them that nothing contains lead or nickel, and nothing is plated. Those familiar with metals give me the thumbs up, but I get a lot of blank stares and assumptions about what’s what. To help those blank stares and assumptions, I’m going to fully explain the differences between the multitudes of metal and metal-like materials used to make jewelry, and why I choose to work with certain metals over others. It’s of great importance to know what you’re buying when making a jewelry purchase. You want something that will last, won’t cause an allergic reaction, and is priced correctly. (Trust me, I’ve seen some pricey jewelry on the market comprised of the cheapest metals. No one wants to get scammed.)
When it comes to jewelry metals, we can break them down into two general categories: base metals and precious metals. Base metals such as copper, brass, iron, and stainless steel are made of materials that are abundant and cost less. Precious metals are called such because historically, they’ve been used as currency, have a high economic value, and resist corrosion or oxidation. Metals like gold, silver, platinum (and those within the platinum family–rhodium and palladium) fall into this category. I will be discussing the precious metals in this article, while next month, I’ll tackle the base metals.
Most high-end jewelry is made of precious metals. Pure gold and pure silver are too soft to be used in most jewelry pieces, so they're usually mixed with other metals, creating an alloy. This is where the karat (or carat) system for measuring gold comes in. 24k gold is pure gold; 14k gold is 14 parts pure gold and 10 parts something else--usually silver, copper, nickel or zinc. The lower the “k” number, the less pure gold in the piece. Changing the amount of the metals in the alloy creates the different colors of gold: rose gold is made from a mixture of gold and copper while white gold is an alloy of gold and white metals (nickel, silver, or palladium) and usually coated with rhodium for a shine.
When denoting the purity of silver, an extension of the karat system called millesimal fineness is used and gives specific names to standardized silver alloys. Sterling silver is comprised of 92.5% silver and 7.5% copper. It is commonly used in many jewelry applications because of its hardness and lovely silver tone. Britannia silver is 95.83 silver, 4.2 % copper (and had a great origin story.) Argentium silver is 93.5% silver and 6.5% germanium (an elemental metalloid.) Fine silver is nearly pure, at 99.9% silver and only used in specific applications. Standardized silver is often stamped: .925 for sterling, .958 for Britannia, .960 for Argentium (oddly enough), and .999 for fine silver. Any other silver markings--such as Mexican silver or Montana silver--do not guarantee any silver content and are not standardized.
Most of my silver jewelry is made of sterling silver, though I do use a small amount of fine silver for certain applications, such as the top bezel wire in my bezel-set pieces. It’s soft enough to push the top of the wire over the stone, setting it in place. I then work-harden it with a burnisher and tumble it for a few hours. Sterling will tarnish (oxidize) because of its copper content, but can easily be cleaned with a paste of baking soda and water or fine grade steel wool for heavy oxidation. Refrain from using commercial jewelry cleaners--they can be corrosive and damage gemstones and pearls.
There is a lot of jewelry on the market that is gold- or silver-plated. Perhaps you’ve purchased what you thought was a silver necklace, then after being worn a few times, it “changes” color. Perhaps your skin has even turned green. Chances are, you’ve purchased plated jewelry. A plating uses the tiniest amount of a precious metal, electroplating it to the surface of a base metal, usually copper but sometimes brass or stainless steel. This plating is easily worn away, quickly revealing the color of the base metal. The green left on your neck or finger is a result of the base metal (copper) reacting with oxygen and your skin oils. I’ve seen expensive, “exclusive” brands use plated metals, so be sure to know what you’re buying!
Contrary to plated metals, gold- and silver-filled metals, when used in jewelry applications, are usually higher-end, cost more, and can even be considered heirloom pieces. Filled metal is not actually filled with gold or silver, but the other way around—a thick coating of a precious metal is applied to a base metal core. Though it sounds similar to gold- or silver-plated, there's a big difference between them: the amount of precious metal used is far greater than for plating. Also, filled metals require that a minimum percentage of its total final weight contain a precious metal: for silver, it's 1/10, and for gold, it's 1/20. Sometimes the fraction is stamped somewhere on the metal. The precious metal is completed sealed over the base metal, so there is no risk for allergic reactions.
Though costing substantially more than plated metals, filled metals are a great way to get the look and feel of karat gold and sterling silver without the price tag of precious metals. I use 14k and 18k gold-filled wires in my work. I love it because it’s durable and always beautiful. I’ve hammered gold-filled wires nearly flat, and the gold is still lovely and shines brightly. Unless examined by a jeweler, no one will know the gold-filled earrings aren’t solid gold (and, as we've discussed, solid gold jewelry usually isn't pure gold either!)
Another precious metal commonly used in jewelry is platinum, though platinum is one of the rarer metals found on earth (30 times rarer than gold,) and therefore is more expensive. When used in jewelry, platinum is usually mixed in an alloy with other metals in the platinum family. However, to be truly labeled "platinum jewelry," the metal must include at least 90% platinum and will be stamped with "PLAT." Due to its durability and resistance to corrosion, platinum has become a popular metal to be used in wedding and engagement rings.
There is a subcategory of precious metals called “noble metals.” I won’t go too much into noble metals–it can be a confusing topic, as definitions vary between different fields of study. However, the main characteristics of noble metals are that they are non-corrosive and non-reactive. All precious metals fall into the category of noble metals. So why bring it up here? Titanium. Titanium is a noble and a precious metal, and it is the exceptionally non-corrosive and non-reactive properties that make it so important in my jewelry making. I use it specifically for customers with severe metal allergies – mostly for ear wires. Titanium is also used in joint replacements and medical implants because it’s the most hypoallergenic metal, as well as being the hardest natural metal (three times stronger than steel) and lightweight. Be careful, however, when buying a titanium ring, as titanium cannot be soldered or resized, and fingers tend to change size as we age.
Cobalt, palladium, and tungsten are all also strong, scratch-resistant, and hypoallergenic metals. They are less expensive than the “big three” precious metals (gold, silver, and platinum) and cobalt and palladium are much lighter. They all have a silvery-white shine like silver or platinum but won’t cause as much alarm when looking at the price tag. Palladium should be checked to make sure that it is 90% palladium. Both cobalt and tungsten (from the Swedish word tung and sten meaning “heavy stone”) are perfect for wedding bands or those who live active lifestyles, as they are less likely to be damaged or to corrode.
Lastly, the very rare rhodium is a white metal that is often used to make rings, since it doesn't tarnish and is very durable. Very little of it is mined each year, so it is extremely expensive--10 times the cost of gold. Rhodium is often used as plating on silver jewelry to enhance the strength.
Next month, we’ll take a look at some of the base metals I use in my jewelry. Feel free to comment below or email me with any questions you have about metals or jewelry making in general!