4 Metal Surface Finishes

The plating process involves submerging metal items in a solution bath and using an electric current to deposit dissolved metal ions on the surface. It requires special skills, equipment and chemicals. Plating is the final step when manufacturing a finished jewelry product. Many manufacturers send out products to a specialized plating facility instead of doing it in-house. Not all jewelry pieces and findings are plated but it is becoming more common.

There are two reasons to plate an item. First, plating can alter the appearance of a metal. Gold plating is often applied over less expensive metals to give the look of solid gold at a lower price. Ruthenium is now a popular plating finish because of its striking black color. Second, plating is often used as part of finishing to give items a brilliant, evenly colored surface. Some items are easier to plate than to finish with other methods. Plating is especially common on jewelry chain, for example.

In the jewelry industry you should properly describe items by the primary material in the piece and then include details on plating. You should never call a gold-plated silver item “gold” because it would be misleading. It can be properly described as silver with gold plating or gold-plated silver. Similarly, silver items with ruthenium or rhodium plating should still be called “silver” along with a disclosure about the surface finishes.

Ruthenium – With its flat black, gun-metal shine, ruthenium is a striking contrast next to polished metals. This makes it a perfect material in mixed metal jewelry. It is highly resistant to wear. Because ruthenium itself is hard and brittle, the plating process is slower and therefore more expensive. It’s part of the platinum group of metals (Ru).

Gold – Gold plating over brass or sterling silver is a very common practice in jewelry. It consists of a thin layer of solid gold (less than a fraction of a percent) that is electroplated onto the base metal. As the gold layer wears out over time, tarnishing will begin to show on the piece where the base metal is exposed. Vermeil is a heavy layer of plating. Gold plating is often applied over gold-filled as well. The plating step adds a higher polish to the metal and evens coloration that can vary in raw gold-filled material. However, it is important to emphasize that gold-filled material is not plated even though plating may be applied as a finishing technique.

Rhodium – Very pricey but the result is a beautiful, steely look to the metal. Rhodium is more gray than silver. The thickness on rhodium plating varies greatly by manufacturer, but the thicker the rhodium, the more tarnish resistant it is. It’s the perfect plating for diamond jewelry because it reflects the sparkly diamonds and makes it difficult to distinguish where the stone ends and the metal begins. It is frequently used in pearl jewelry to delay tarnishing because it is so difficult to clean metals alongside fragile pearls. It’s part of the platinum group of metals (Rh). Note: properly rhodium plated sterling items use a nickel barrier layer between the silver and the rhodium to prevent ion migration across the layers. People with nickel allergies should generally avoid rhodium plated items.

Fine Silver – Many people wonder why you would plate a sterling item with more silver. Good question! Fine silver plating over sterling brightens up a silver piece and is more resistant to tarnishing compared to sterling silver because of the higher content of silver on the surface. It is the copper in sterling alloys that oxidizes the metal most rapidly. Plating with fine silver is often more effective and efficient than surface finishing with tumblers, abrasives and ultrasonics.

It’s important to note that any surface plating will wear off over extended periods of time depending on wear and environmental conditions.

Some surface finishes are added to delay the onset of oxidation or tarnish on silver alloys. It is impossible to prevent tarnish on silver forever, but, you can increase the time it takes for oxidation to begin. The efficacy of anti-tarnish treatments will depend on many environmental factors so you cannot pinpoint a lifespan with any precision.

It is especially important to know about treatments if you plan to apply patinas to a piece. Any anti-tarnish treatment will prevent even patination on a metal item. Results will be splotchy and unpredictable. If you wish to oxidize your jewelry findings, it is best to select items without anti-tarnish. At Halstead, you will find that all of our items contain disclosure on anti-tarnish treatments in the item detail information online.

• Spray – Spray application of a chemical coating. Adheres quickly, coats surface.
• E-coating – Electric current bonds an extremely thin plastic film to surface, lasts longer than spray. Acetone will strip away e-coating but you risk damaging the metal underneath.

Note: We do not recommend removing anti-tarnish treatments. Results will vary.

Tools and equipment can be used to finish metals or apply textures for visual effect. Many common practices are described below.

Polished or Brite– reflective, mirror-like. Metalsmiths will tell you that polished, smooth surfaces take work to achieve. Even though we would generally say these items have no surface effect, it is important to understand that many polishing steps are still needed to achieve this high shine. Hand fabricated pieces will be filed, sanded and polished with hand tools. Mass produced items will go through many hours in tumblers and ultrasonic baths. Sometimes, plating will even be applied to achieve a high polish as described in the plating section above.

Satin – dully polished, diffused glow. A satin finish can be achieved with abrasives or brushes. Satin items are not reflective or shiny. Instead, they have a soft, warm glow.

Brushed – tiny wire brushed marks. Wire brushes are usually used for this surface effect. The metal is brushed in only one direction so you can see visible striation when you look closely.

Matte – dull, no reflection. Matte and satin are often used interchangeably. Matte effects are slightly more dull than satin so there is no glowing reflection of light off the surface.

Stardust (Sandblast)– grainy, sparkly. Stardust can be achieved with advanced machine tooling that uses diamond heads to make tiny nicks across the surface. Obviously, this technique removes material and is not appropriate for plated items or gold-filled since the surface layer would be damaged. Instead, gold-filled stardust is either an application of glitter-like gold dust on the surface or tooling that indents the surface but does not pierce it.

Diamond Cut – angle cutting. Diamond cutting is so named because it requires diamond tool heads that can make extremely precise, sharp cuts in the surface of the metal. Diamond cutting removes material from the surface to create mirror-like facets that catch the light. Contemporary jewelry sometimes has diamond cutting on plated items to create visual interest with the contrast between the primary metal and the surface plating. Diamond cut ruthenium is particularly striking because of the interplay between white sterling and black ruthenium.

Hammered – Traditional hammering is done with a round, ball-pein head to create soft indentations. Modern metalsmiths now use a wider array of hammer heads to apply textures.

Sparkle – sharp, angled strikes with machined hammer heads. The sparkle solution is an innovative development to  create the look of diamond cutting without actually piercing the surface and removing material. This maintains the integrity of the primary metal and is especially useful for a layered material like gold-filled.

Patinas are surface effects that change the color of a metal through a chemical reaction. The most common patina in silver jewelry is oxidation with liver of sulfur. This treatment accelerates and intensifies tarnishing to create a dark, nearly black surface. Patinas are usually applied to an entire piece and then the surface may be polished and finished to leave the dark color in relief only. This technique is commonly called antique finishing because it makes the metal look older or more rustic.

Antique – oxidized finish.

Note: patinas can be stripped away with abrasives or chemical cleaning.

For more information and examples of surface finishes for metal, take a tour of our sister website at EarringsMarket.com and take a closer look at your favorite findings, chains and other jewelry supplies. Visit our Facebook page for beautiful ideas and inspiration.