Precious metals have been used in jewelry for thousands of years because of their beauty, durability and ability to be shaped into intricate forms. Gold, silver and platinum each have distinct properties that influence how jewelry looks, feels and wears over time.
This guide explains the precious metals commonly used in jewelry, including gold karats, sterling silver, platinum, metal alloys, keum-boo, gold plating, vermeil and jewelry finishes.
Precious metals are naturally occurring metallic elements valued for their rarity, appearance and useful physical properties. In jewelry, the most familiar precious metals are gold, silver and platinum.
Pure precious metals are not always ideal for jewelry in their natural state. Gold and silver, for example, are often combined with other metals to create alloys with characteristics better suited to jewelry making and everyday wear.
An alloy is a mixture of two or more elements, at least one of which is a metal. Jewelers use alloys to modify properties such as strength, hardness, color and workability.
The amount and type of metal added can significantly influence the finished material. This is why different gold alloys can have different colors and why sterling silver behaves differently from pure silver.
Gold has been used for jewelry and decorative objects for thousands of years. It is valued for its warm color, resistance to corrosion and exceptional ability to be shaped and worked.
Pure gold is very soft, so gold used for jewelry is commonly alloyed with other metals. The proportion of pure gold in the alloy is expressed in karats.
The karat system describes the proportion of pure gold in a gold alloy. Pure gold is designated as 24K, while lower karat numbers indicate that the gold has been combined with a greater proportion of other metals.
The alloying metals affect more than purity. They can influence the color, hardness, strength and working characteristics of the finished gold.
Oliver Hampel uses 18K gold in many of his precious-metal jewelry designs.
Gold alloys can be produced in different colors by changing the metals combined with the gold.
Yellow gold retains the familiar warm color associated with gold. Its alloy composition is selected to provide additional strength while maintaining a rich yellow appearance.
White gold is created by combining gold with metals that produce a paler, more neutral appearance. Many commercially produced white-gold pieces are also rhodium plated to create a bright white surface.
Rose gold receives its warm pink or reddish color primarily from the copper used in the alloy. The amount of copper and other alloying metals influences the final shade.
Pure silver is relatively soft, so silver used for jewelry is commonly alloyed with another metal to improve its strength and durability.
Sterling silver contains 92.5% silver and 7.5% other metals. This is why sterling silver jewelry is often marked 925.
Sterling silver can naturally tarnish as the metal reacts with compounds in the surrounding environment. Tarnish is a surface reaction and does not mean that the silver itself is damaged.
Sterling silver is an important material in Oliver Hampel's work and is frequently used to create sculptural forms with matte and satin surfaces.
For information about cleaning and maintaining sterling silver, visit our Jewelry Care Guide.
Platinum is a naturally white precious metal known for its density, durability and resistance to corrosion. It is heavier than gold or silver and is commonly used in fine jewelry, particularly for rings and gemstone settings.
Platinum jewelry is generally made from alloys containing a high percentage of platinum combined with smaller amounts of other metals to improve its working properties.
Unlike white gold, platinum is naturally white and does not require rhodium plating to achieve its color.
Keum-boo is a traditional Korean technique in which thin sheets of high-karat gold are bonded to the surface of silver. The technique creates a strong visual contrast between the warm color of gold and the cooler tone of silver.
Selected Oliver Hampel sterling silver pieces incorporate 24K gold using the keum-boo technique. Rather than covering the entire piece, the gold becomes part of the surface design and provides a distinct contrast of color and material.
Gold plating uses a thin layer of gold applied over another metal. Because the gold is present only on the surface, plated jewelry differs fundamentally from solid gold jewelry.
The appearance and longevity of gold plating depend on factors such as the thickness of the gold layer, the underlying material and how the jewelry is worn and cared for.
Vermeil is a specific type of gold-plated jewelry in which gold is applied over sterling silver. Standards governing the required gold purity and plating thickness can vary by country.
Plated surfaces should generally be cleaned gently because abrasive polishing can gradually wear away the gold layer.
The final appearance of a metal surface is determined not only by the metal itself but also by the way the surface is finished.
A highly polished finish reflects light strongly and creates a bright, mirror-like surface. Matte and satin finishes diffuse light and create a softer appearance that can emphasize form, texture and subtle variations in the metal.
Textured, oxidized and other specialized finishes can further change the appearance of a piece and may require specific care.
Many Oliver Hampel designs use matte or satin surfaces as part of their visual character. Aggressive polishing can alter these finishes, so cleaning methods should take the intended surface into account.
Oliver Hampel approaches precious metals as both structural and expressive materials. Sterling silver and 18K gold are shaped into contemporary jewelry influenced by nature, organic forms, architecture and structural patterns.
Matte and satin surfaces frequently emphasize the sculptural character of the forms, while gemstones, pearls and contrasting gold details can become part of the composition.
Selected sterling silver pieces also incorporate 24K gold using the traditional keum-boo technique.
Learn more about Oliver's approach to jewelry and design on Meet Oliver Hampel.
Look up jewelry, metalsmithing and precious-metal terminology in our Jewelry & Precious Metal Glossary.
Explore diamonds, colored gemstones, pearls, gemstone hardness and treatments in our Gemstone Guide, or learn how to clean and protect different jewelry materials in our Jewelry Care Guide.
Visit Jewelry Guides to explore all of our jewelry reference resources.
Discover Oliver Hampel's contemporary sterling silver jewelry and 18K gold jewelry.
New jewelry, exhibitions and occasional news from Oliver's studio.
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