Metal Finishing for Jewelry
Jewelry metals are often plated with another metal to give it a certain color and increase its durability. Rhodium is likely the most popular plating material. It is a silvery-white precious metal, too rare to use on its own. Rhodium plating is usually used on white gold and sometimes sterling silver, as it protects the metals from damage and discoloration. Black or colored rhodium is also used to decorate a piece or give it a different tint.
Palladium plating is also used on white metals and even base metals in fashion jewelry. A member of the platinum group, it has a natural silvery color which is strong, lightweight, and durable. Though it is considered to be one of the rarest metals, you can still find 95% pure palladium jewelry.
Also a member of the platinum group, ruthenium is sometimes used to plate jewelry to give it a dark, silvery-gray or jet black color. Ruthenium plating is very strong and resistant to scratches, which makes it a good choice for soft metals. And just like rhodium, ruthenium is too rare to use as the primary material for jewelry.
A majority of jewelry has a polished finish, which involves buffing the metal out to a mirror-like shine. To make a metal go from shiny to sparkly, the surface could be diamond-cut, using sliced faceting to create a reflective shimmer, similar to that of diamonds.
But high shine isn't for everyone. A matte finish provides a non-reflective look applied by first polishing and then abrading the surface. A satin finish also offers a lusterless appearance, but is silky smooth with a frost-like facade. Though not as dull, a brushed finish can give low-luster to a piece, using a very fine texture that looks as if it were applied with a wire brush.
If you like the tactile nature of a brushed piece, then you'll love textured jewelry! Texturing is a unique and varying technique which creates an interesting surface either by hand and with machinery. Florentine is a special kind of texturing formed by engraving a cross-hatched pattern along a surface. Hammered jewelry also provides texture, crafting a dimpled surface which looks as if it were applied through various strikes of a hammer.
Special Finishing Techniques
Jewelry designers have become quite creative over the years, discovering new ways to give metals a different look and feel. One fairly new trick is the gunmetal finish. Gunmetal is sometimes called a "hematite finish" because of its likeness in appearance to a hematite stone, which has a dark, silvery gray color. This finish is achieved through many different techniques, sometimes involving black rhodium, ruthenium, or even a special gel which is rubbed over the surface to change the color.
Another trend that has surfaced is the vintage-look. To make jewelry appear old (yes on purpose) an antique finish is usually applied, either with a scattered black coating, or though oxidization. When a piece is oxidized, especially sterling silver, it reacts with oxygen to create a discoloration or tarnishing, making it appear weathered.
An industrial technique called PVD has also recently made its way into modern stainless steel jewelry designs. An alternative to plating, PVD, which stands for "Physical Vapor Deposition," is a layer of colored film that forms over stainless steel in a vacuum chamber. PVD is used often in sporty watches because it is durable in harsh outdoor conditions. It often has a sheen black color, but is presented in other metallic colors as well.