When it comes to purchasing jewelry, many individuals will usually have a preference for the type of metal used in its creation. There are many different metals to choose from, depending on the piece’s intended use and final design. This article aims to cover the most common metals used in jewelry making and draw attention to their specific strengths and weaknesses.

When it comes to high-quality jewelry, the types of metals used are almost universally “precious metals.” Of course, cheap or costume jewelry will often use more common and less expensive metals like brass, aluminum, or stainless steel, but for jewelry that will last a lifetime and be less likely to cause skin reactions, it is best to purchase from a custom jeweler like D. Cole Jewelers that will use fine materials in their construction. Precious metals are rare metals of high economic value. They are usually not very reactive, malleable enough to be formed into any desired shape, and have a high luster. Historically, many precious metals were used as currency.

When most folks think of precious metals, the first that come to mind are gold and silver. These are the best known, but six other metals are precious, known as platinum group metals. Besides the obvious platinum, this includes palladium, rhodium, ruthenium, iridium, and osmium. These metallic elements, along with silver and gold, are all clustered together on the periodic table.

Gold

Because of its unique yellow color, gold is one of the easiest metals to recognize. Gold is the oldest known metal used by humans because it can be found in its pure form in nature. The oldest gold artifact found to date is a tiny bead found in Bulgaria, estimated to be from somewhere between 4600 to 4500 BCE. Gold is often culturally associated with ideas of high value, purity, perfection, divinity, and wisdom. Gold is popular because of its beautiful color and luster, its malleability which allows it to be shaped easily, and its tendency not to corrode or fade. However, because gold is so soft, it is often blended with other metals, like silver or copper, for example, to strengthen it.

Because gold is often blended with other metals, jewelers use a system to rate the purity of a gold alloy, referred to as Karat. The ratings are as follows:

·        24 Karat: 99.9 percent pure gold

·        22 Karat: 91.7 percent pure gold

·        18 Karat: 75 percent pure gold

·        14 Karat: 58.3 percent pure gold

·        12 Karat: 50 percent pure gold

·        10 Karat: 41.7 percent pure gold

Gold jewelry can also use other alloys in its creation. Solid gold means that the entire piece is not hollow and it contains at least 10 karat gold. A much cheaper, but less durable option is gold-plating, where a different metal, often copper, is coated with a thin layer of gold 10 karats or greater. Because the layer is so thin, it will often wear away with frequent use. A more durable option is gold-filled. Where gold-plating uses an electrical current to create a very thin layer of gold, gold-filling sandwiches the core metal between two layers of gold, heating and rolling the piece for a much thicker layer of gold. The last tier of gold coating is gold vermeil, where a base metal of silver is gold plated.

Gold also can come in many colors depending on what other metal it is blended with. “Yellow gold” refers to pure gold because it retains its signature sunny hue. “White gold”, which has a pale color is usually gold mixed with nickel, but can also include zinc or palladium. Gold mixed with iron becomes “blue gold,” with a bluish tinge to its color. Lastly, the trendy pinkish-red material known as rose gold is a mix of gold and copper.

Silver

Silver, like gold, was known to prehistoric humans and thus the nature of its discovery is unknown to modern humans. Because native silver is more reactive than gold, in antiquity it was an even more rare resource than gold. Like gold, because it is malleable, not very reactive, and beautiful, its most common historical use was for ornamentation and coinage. However, today, because it is the most highly conductive element of both heat and electricity, it is extremely useful in electronics. Silver also has practical applications as an antimicrobial coating in medical equipment and is integral to the chemical reactions of traditional photography.

Also like gold, silver is often blended with other metals, usually copper, to increase its strength. Silver’s purity is denoted by its percentage. 800 silver is 80 percent silver, the remaining 20 percent being copper or another metal. Silver that contains 92.5 percent silver (with no more than 7.6 percent of any other metals is called 925 sterling silver, a standard defined in 1300 by King Edward the First of England. Similarly, 950 sterling silver is at least 95 percent silver, while fine silver contains 99.9 percent silver. Fine silver is not common in jewelry, though sometimes is used over as a coating over sterling silver to make it shine.

Platinum

Platinum is a silvery-white metal that is usually strengthened for use in jewelry making by nickel, osmium, or iridium. Platinum, along with the other five metals of the platinum group are the rarest, and therefore most expensive of the precious metals. Metals in the platinum group are 15-30 times more rare than gold. Platinum itself is so rare, that all of the platinum ever mined would fit into an average house. This rarity is the reason these metals are not as commonly used in jewelry, because in terms of durability, platinum outperforms silver and gold by quite a bit.

Like silver, platinum’s purity is defined by its percentage. Pure platinum is labeled Pt1000. In fine jewelry, Pt950 and Pt900 (95 percent and 90 percent platinum, respectively) as the most commonly used. Any percentage under Pt900 is not considered fine platinum.

Palladium

Palladium is very similar to platinum. It is rare and highly malleable, while also able to absorb high amounts of hydrogen and maintain stability at high temperatures. In both rarity and price, it falls somewhere between platinum and gold. Unlike the previous three metals, which were used by ancient peoples, palladium was not discovered until 1802 by William Hyde Wollaston, an English chemist and physicist. It is usually used as an alternative to platinum in “white gold” alloys.

Rhodium

Rhodium was also discovered by William Hyde Wollaston in 1803. It is highly reflective and silvery in color, with high resistance to corrosion and a high melting point. It is also commonly used in alloys, as well as in plating. It gives the piece a highly reflective white surface, and when used to plate sterling silver can help to protect against tarnishing. Outside of jewelry, its most common use is in the catalytic converters of cars.

Ruthenium

Ruthenium is often used in alloys to increase the durability of the piece. Although all six platinum group metals were used in naturally occurring alloys by pre-Columbian Americans, the individual elements were not isolated until the 18th century. Ruthenium itself was officially isolated in 1844 by Russian scientist Karl Ernst Claus, although other researchers might have isolated it earlier but not definitively. Its most common industrial use is in wear-resistant electrical contacts and thick-film resistors.

Iridium

Iridium, also commonly used in alloys, is one of the densest metals. It also has the distinction of being the most corrosion-resistant element, while also boasting one of the highest melting points. Iridium was first discovered in 1803 by Smithson Tennant, who named the element after the Greek goddess Iris, goddess of the rainbow. This was because the salts it produces in certain chemical reactions have varying striking colors. The metal itself is a silvery-white color like the other platinum group metals. Another interesting property of iridium is its rarity. Iridium is extremely rare in the crust of the earth, however, it is found in a higher abundance in meteorites.

Osmium

The last precious metal is osmium. This metal, while it has most properties in common with the other platinum group metals, has a few things that set it apart. First, it is the densest naturally occurring element. It is also naturally very hard and brittle. Lastly, and perhaps most distinctly, it has a rather unpleasant odor, often described as ashy or smoky. In fact, its name is derived from the Greek word “osme” meaning smell. All of these reasons mean that it is not very commonly used in jewelry making, although it does occasionally show up as an alloy. More often though, it is used in applications that require very hard materials, like fountain pen nibs and electrical contacts.

The Bottom Line

When all is said and done, the precious metals commonly used in jewelry have their own strengths and weaknesses, as well as interesting applications outside of the world of jewelry making. The decision usually comes down to personal preference and the buyer’s own aesthetic and practical values. Having more information on the specific metals available empowers the buyer to make an informed decision and acquire the specific jewelry piece of their dreams.