Jewelry Metals 101: Gold, Silver, and Platinum
Table of Contents
- What are the Noble Metals?
- Common Metallurgy Terms
Since time immemorial, jewelers have used just about every type of metal they
Jewelry Metals 101: Gold, Silver, and Platinum
Table of Contents
- What are the Noble Metals?
- Common Metallurgy Terms
Since time immemorial, jewelers have used just about every type of metal they can acquire for their creations. When new alloys and metals emerge, such as titanium and stainless steel, they eagerly embrace them. Jewelers adapt them for jewelry making and create beautiful pieces from them.
Fashion trends utilizing trendy metals come and go. However, three jewelry metals have withstood the test of time and continue to have a strong presence in modern jewelry. They are gold, silver, and platinum. These three metals belong to a group of elements known as the noble metals.
What are the Noble Metals?
Chemically, noble metals resist oxidation and corrosion in moist air. They also possess varying degrees of resistance to acids. This group includes the following elements: ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, and gold.
In addition to noble metal properties, gold, silver, and platinum posses the following characteristics:
- These metals occur worldwide, but not in large enough quantities to render them less valuable.
- They are considered precious metals and have been used as currency (a store of value).
- Many cultures, historically and currently, consider these metals beautiful, sensuous, and glamorous, which increases their appeal.
- These metals also possess malleability, which makes them practical choices for jewelry making.
For all these reasons, the trio of gold, silver, and platinum continue to enjoy considerable popularity as jewelry metals.
Although long coveted for its beauty, gold possesses physical properties that have also captivated humanity. Since gold never tarnishes and has great workability, many jewelry designers and makers prefer it to other metals. In fact, a single ounce of gold can be stretched into a thread more than 50 miles long. You can also roll that quantity into a sheet that covers 100 square feet in area. If properly cared for, gold can last indefinitely, which makes it a prized metal to designers as well as consumers. It doesn’t oxidize or corrode, and only a handful of rare acids or hot chlorine bleach can damage it.
Recent studies suggest that gold originated in the far reaches of the universe, billions of years ago. It arrived as dust on Earth in its infancy. Gold has witnessed many transformations, and the material made into jewelry may continue to do so. Gold can be reused by melting down old gold objects and reforming the gold into new pieces. For example, old coins and broken pieces of jewelry can be melted down and reused to make new gold jewelry.
Despite gold’s desirable properties, it does have one significant drawback: softness. This means it wears out easily. (This quality differs from gemological/mineralogical measurements of hardness as resistance to scratching). However, mixing gold with other metals creates gold alloys that are stronger, more durable, and better suited for jewelry use. While jewelers do use pure gold for some jewelry pieces, these dent and show wear so readily that most people don’t wear pure gold jewelry on a regular basis.
Metals commonly alloyed with gold for jewelry purposes include: silver, copper, nickel, iron, zinc, tin, manganese, cadmium, and titanium. In addition to enhancing gold’s strength, alloying changes some of its other properties, too. For example, some gold alloys stain skin or cause allergic reactions. The gold itself doesn’t cause these reactions. Rather, the alloyed metals do.
When discussing gold and its alloys, the term karat indicates the purity of the gold. (Don’t confuse karat with carat, which is a unit of measurement used to describe gemstone weight). Pure gold, which contains no other metals, is termed 24-karat gold. So, a 50/50 alloy, half pure gold and half other metal or metals, is 12-karat gold. Alloys used in jewelry making range from 9-karat gold, approximately 37% pure gold, to 24-karat gold. They are required to be stamped and hallmarked according to purity.
A newer alloy becoming popular on the jewelry scene consists of 99% gold and 1% titanium. This allows the alloy to retain nearly all its gold color while providing improved durability.
|Karat||Parts Gold||Percent Gold||Other Marks|
The color of gold changes when alloyed. For example, mixing copper with gold creates a darker yellow color. Adding nickel plus zinc, copper, platinum, or manganese produces white gold. Typically, white gold doesn’t contain silver, which softens gold and gives it a green tint. Other gold alloy colors include green, red, and blue