Dichroic glass, also known as fusion glass, is glass that has been treated with various metal oxides to give it the appearance of multiple colors. Dichroic glass was originally developed for use in the American space program, but it is now widely used in jewelry and art. The name is derived from a Greek word that means “two colors.”
The National Aeronautics and Space Administration (NASA) began experimenting with treated glass in the early twentieth century to create astronaut face-plates that would block harmful light spectrums. Dichroic glass is made using a process that fractures and separates lightwaves using fine layers of metal oxides. The resulting substance is used on satellite mirrors and scientific instruments, among other things. It’s also on mirrors and camcorder lenses, among other commercial items.
Glass must be sprayed with micro-layers of metals, such as titanium, chromium, gold, zirconium, and aluminum, to create dichroic glass. This is done in a vacuum chamber, where the metals are vaporized and fused to the glass in very thin layers. The fusion process causes light to fracture creating a crystalline structure on the glass. Each piece of dichroic glass has at least three colors: the reflected color, the color of the glass, and a second refracted color visible at a 45-degree angle. The procedure necessitates specialized equipment and can be quite costly to manufacture.
The process of treating the glass in this way is similar to that of making Murano glass in Italy. Metal oxides are used to create color and alter translucency in this process, which has been used in Italian jewelry and ornamentation for hundreds of years. Metal elements are added to a super-heated silicate just before it hardens, allowing the colors and refractions to be interwoven with the actual glass in Murano glass. Murano glass often appears to be multiple shades of one color, rather than the iridescent or rainbow colors seen in dichroic glass, due to the mixing process.
Dichroic glass is frequently used in jewelry as beads. The dichroic layer of glass is fired in a kiln alongside other layers of glass to achieve this. The glass can be fired multiple times at various settings, depending on the desired effect, and more layers can be added if necessary. Depending on the type of metals used in the vacuum process, dichroic glass beads can be made in a variety of different shades.
Dichroic jewelry comes in every color of the rainbow and can be found in jewelry stores and online. Because the process is costly, a single pendant or large bead made of glass may appear to be relatively expensive. Individual beads cost around $20 USD and up, while bracelets and necklaces made up of the beads start at around $70 USD. Earrings in the shape of rectangles or triangles can be found for around $18 USD.