Titanium and niobium are members of the reactive metals, which have the unique property of taking on color when exposed to electricity or heat. Ring styles that have color are available in any of the following shades:
Durability of the colors
You cannot scratch off the color with a fingernail, and the color will not fade from sunlight or solvents, including acetone. Color that is anodized onto smooth titanium or niobium could scratch off with a sharp object. That’s why when we color our rings we use either narrow, deep grooves that will trap the color or heavily textured areas where the color may wear off the high ridges, but will remain in the deep crevices.
How we get the colors
When electricity is used to create colors on niobium and titanium, the process is called anodizing. During anodizing, the metal is immersed into an electrolytic bath through which an electric current is passed, causing an oxide layer to form on the surface of the metal.
Light striking the surface of the oxide layer and the metal below will result in two refracted light rays which reinforce each other and produce different colors depending on the thickness of the oxide layer. This phenomenon, called optical interference, is responsible for holographic images and the iridescent colors in butterfly wings and soap bubbles. The colors are called interference colors, and were first described by Issac Newton in the 1670s.