Precious Metals Guide
Precious metals have been used for adornment throughout history. There is evidence, for example, of gold jewelry being worn in ancient Sumeria around 3000 BCE, used for chains and jewelry in ancient Crete, mined underground in ancient Egypt, and worked and worn in ancient Peru. These lustrous elements and alloys have also been used for everything from monetary systems to religious artifacts--though we happen to like them best when they're used for jewelry!
There are a number of things to consider when choosing a metal. First, what color do you like best? Precious metals can range from shining yellow to warm gold to icy white, and each color can work in a variety of styles. When thinking about metals, you'll also want to consider durability. Read below for more information about the different precious metals.
One of the world's most precious metals, gold dates back to the dawn of mankind. The Egyptians equated gold with the sun, the giver of life, and reserved its use for pharaohs only. The ancient Etruscans created meticulously hand wrought objects using fine granules and threads of gold, a technique still practiced today.
Measuring the Purity of Gold
Many people will recognize "24 karats" or "18 karats" as some kind of measure of gold (not to be confused with "carats" which are a measure of diamond weight), but less realize that karats are actually a measure of the metal's purity. One karat is equal to 1/24th pure gold in an alloy. Subsequently, pure gold itself is 24 karats. Something that is 14 karats, then, means that 14 parts of the total 24 are pure gold, and they are mixed with 10 parts of other metal. In the US, the phrase "karat gold" refers to a gold alloy of no less than 10 karats.
This chart lays out a few examples of gold's "fineness" or percentage of pure gold:
|Karat||Pure gold content|
Before you assume that 24k gold is the best gold, however, it is important to point out that gold is a rather soft metal and that 100% pure gold (24k) is often considered too soft to use in jewelry. Instead, gold is mixed or alloyed with one or more other metals to produce optimum strength and color. The National Gold and Silver Marking act is a federal law that requires that all gold jewelry to include accurate karat marks, along with a registered US trademark, to assure customers that the gold is actually of its specified quality. If you're curious to find those marks, you can stop by your local Ben Bridge store and ask a Personal Jeweler to help.
Gold alone is typically too soft to successfully be used in jewelry. But instead of abandoning gold adornments entirely, clever metallurgists decided to combine or alloy gold with other metals to increase its durability and to impact its color. Most of the gold you see today has been alloyed with other metals. Below, you can find a chart detailing some common alloys of gold and the colors they produce:
|Yellow gold||Gold, copper, silver|
|White gold||Gold, nickel, palladium, zinc, copper|
|Green gold||Gold, copper, silver, zinc|
|Pink gold (rose gold)||Gold, copper|
(For the percentage of alloys in a piece of gold jewelry, refer to the karat gold percentage)
Many different finishes are used in gold jewelry to create patterns, designs, or various textures. Some of the most common finishes include:
- High polish: Bright, shiny, and highly reflective
- Satin finish: A soft and lustrous appearance with light parallel lines that sharply reduce metal reflections
- A velvet-like finish with a soft luster and no shine
- A textured finish with chemically or hand-drawn designs or patterns cut into the surface
- A light satin-like finish produced by a stiff metal brush, applied in a linear or circular pattern
- A textured design created by hammering directly onto the metal's surface
White gold is an alloy, or mixture, of gold with other precious base metals such as palladium, silver, platinum, and nickel. Because gold's natural appearance is yellow in tone, it must be combined with a white metal to create a relatively white appearance.
To keep its white color bright, white gold jewelry is typically coated with rhodium. Rhodium is an elemental, non-tarnishing member of the platinum group of metals which is very white, highly reflective, and extremely durable. That said, rhodium is still not impervious to the effects of wear and tear that occur with everyday use. Rhodium-coated white gold may retain its finish for a lifetime or only for a short period of time, depending on how frequently you wear it or your specific body chemistry. If the rhodium finish does wear over time, it can be easily and inexpensively recoated to return to its original brightness.
Though gold is typically considered the most prized metal throughout history, platnium's history is actually just as long and just as luxurious. The ancient Egyptians and Incas both prized platinum and France's Louis XVI proclaimed it the only metal fit for royalty. Legendary jewelers such as Faberge created their timeless designs in platinum, and platinum remains the metal of choice for setting the world's most famous diamonds including the Hope Diamond. Though platinum and white gold have a similar look, platinum has a number of special qualities that set it apart from the other precious metals. Most notably, platinum is an incredibly strong, incredibly pure metal. It resists tarnish, is hypoallergenic, and is generally considered the most permanent of the precious metals.
Platinum is the heaviest of the precious metals, weighing almost twice as much as 24 karat gold. It is one of the world's strongest and most enduring metals, and will hold diamonds and gemstones securely in their mountings. Even after many years, platinum will not wear away or wear down. As with all precious metals, it is possible for platinum to be scratched, but, unlike with gold or other metals, there is actually no material lost in that scratch. Platinum jewelry can easily be given a quick polish to look as good as new.
In the US, platinum jewelery contains either 90% or 95% pure platinum. By comparison, 18 karat gold is 75% pure and 14 karat gold is only 58% pure. Platinum jewelry marked "IRIDPLAT" contains 90% platinum and 10% iridium. When it is simply marked "PLAT", the piece is at least 95% platinum with around 5% ruthenium. While white gold and platinum often look very similar, platinum achieves its clean white look without the significant addition of other metals.
Platinum is incredibly rare, and a tremendous amount of labor goes into mining and refining it. Ten tons of ore must be mined to produce a single ounce of platinum, and processing the ore into pure platinum typically takes around five months. It is only after this processing has been completed that skilled hands can transform platinum into pieces of wearable art.
Palladium is a rare, lustrous, silvery-white member of the platinum group of metals. Like its sister platinum, palladium is hypoallergenic, naturally white, and will remain white with wear. Also like platinum, palladium is both rare and durable: though palladium is 30 times more rare than gold, it has been shown to be 15% more resistant to wear. Palladium is exceptionally durable but weighs less than platinum itself, making it an ideal choice for people looking for strong but light everyday pieces.